{"item": {"cve_id": "CVE-2021-26855", "ghsa_id": "", "osv_id": "", "title": "Microsoft Exchange Server Remote Code Execution Vulnerability", "description": "Microsoft Exchange Server Remote Code Execution Vulnerability", "published_at": "2021-03-03T00:15:12.103", "modified_at": "2026-08-19T19:22:24.100", "vendor": "Microsoft", "product": "Exchange Server", "affected_versions": ["15.00.0", "15.01.0", "15.02.0"], "fixed_versions": [], "cvss_score": 9.1, "cvss_version": "3.1", "cvss_vector": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N", "severity": "CRITICAL", "epss_score": 0.99996, "epss_percentile": 0.99989, "epss_date": "2026-10-06", "is_kev": true, "kev_date": "2021-11-03", "kev_due_date": "2022-05-03", "kev_action": "Apply updates per vendor instructions.", "cwe_ids": ["CWE-918"], "attack_vector": "NETWORK", "attack_complexity": "LOW", "privileges_required": "NONE", "user_interaction": "NONE", "references": ["https://msrc.microsoft.com/update-guide/vulnerability/CVE-2021-26855", "http://packetstormsecurity.com/files/161846/Microsoft-Exchange-2019-SSRF-Arbitrary-File-Write.html", "http://packetstormsecurity.com/files/161938/Microsoft-Exchange-ProxyLogon-Remote-Code-Execution.html", "http://packetstormsecurity.com/files/162610/Microsoft-Exchange-2019-Unauthenticated-Email-Download.html", "http://packetstormsecurity.com/files/162736/Microsoft-Exchange-ProxyLogon-Collector.html", "https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2021-26855", "https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2021-26855"], "source_urls": {"NVD": "https://nvd.nist.gov/vuln/detail/CVE-2021-26855", "CVE.org": "https://www.cve.org/CVERecord?id=CVE-2021-26855", "CISA": "https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2021-26855", "FIRST EPSS": "https://api.first.org/data/v1/epss?cve=CVE-2021-26855"}, "patch_available": null, "workaround_available": null, "sources": ["NVD", "CVE.org", "CISA", "FIRST EPSS"], "reference_items": [{"url": "https://msrc.microsoft.com/update-guide/vulnerability/CVE-2021-26855", "tags": ["Patch", "Vendor Advisory", "vendor-advisory", "patch"], "source": "NVD", "name": ""}, {"url": "http://packetstormsecurity.com/files/161846/Microsoft-Exchange-2019-SSRF-Arbitrary-File-Write.html", "tags": ["Exploit", "Third Party Advisory", "VDB Entry", "x_refsource_MISC", "x_transferred"], "source": "NVD", "name": ""}, {"url": "http://packetstormsecurity.com/files/161938/Microsoft-Exchange-ProxyLogon-Remote-Code-Execution.html", "tags": ["Exploit", "Third Party Advisory", "VDB Entry", "x_refsource_MISC", "x_transferred"], "source": "NVD", "name": ""}, {"url": "http://packetstormsecurity.com/files/162610/Microsoft-Exchange-2019-Unauthenticated-Email-Download.html", "tags": ["Exploit", "Third Party Advisory", "VDB Entry", "x_refsource_MISC", "x_transferred"], "source": "NVD", "name": ""}, {"url": "http://packetstormsecurity.com/files/162736/Microsoft-Exchange-ProxyLogon-Collector.html", "tags": ["Exploit", "Third Party Advisory", "VDB Entry", "x_refsource_MISC", "x_transferred"], "source": "NVD", "name": ""}, {"url": "https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2021-26855", "tags": ["Patch", "Vendor Advisory", "x_refsource_MISC", "x_transferred"], "source": "NVD", "name": ""}, {"url": "https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2021-26855", "tags": ["US Government Resource", "government-resource"], "source": "NVD", "name": ""}], "cvss_v4_score": null, "cvss_v4_vector": "", "cvss_v4_severity": "", "nvd_status": "Analyzed", "cna": "microsoft", "date_reserved": "2021-02-08T00:00:00.000Z", "ssvc": {"options": {"Exploitation": "active", "Automatable": "yes", "Technical Impact": "total"}, "version": "2.0.3", "timestamp": "2021-03-01T00:00:00+00:00", "role": "CISA Coordinator"}, "affected_products": [{"vendor": "Microsoft", "product": "Exchange Server", "ranges": ["2013", "2016", "2019"], "first_unaffected": [], "source": "NVD"}, {"vendor": "Microsoft", "product": "Microsoft Exchange Server 2013 Cumulative Update 21", "ranges": ["de 15.00.0 à 15.00.1395.012 (exclue)"], "first_unaffected": ["15.00.1395.012"], "source": "CVE.org"}, {"vendor": "Microsoft", "product": "Microsoft Exchange Server 2013 Cumulative Update 22", "ranges": ["de 15.00.0 à 15.00.1473.006 (exclue)"], "first_unaffected": ["15.00.1473.006"], "source": "CVE.org"}, {"vendor": "Microsoft", "product": "Microsoft Exchange Server 2013 Cumulative Update 23", "ranges": ["de 15.00.0 à 15.00.1497.012 (exclue)"], "first_unaffected": ["15.00.1497.012"], "source": "CVE.org"}, {"vendor": "Microsoft", "product": "Microsoft Exchange Server 2016 Cumulative Update 10", "ranges": ["de 15.01.0 à 15.01.1531.012 (exclue)"], "first_unaffected": ["15.01.1531.012"], "source": "CVE.org"}, {"vendor": "Microsoft", "product": "Microsoft Exchange Server 2016 Cumulative Update 11", "ranges": ["de 15.01.0 à 15.01.1591.018 (exclue)"], "first_unaffected": ["15.01.1591.018"], "source": "CVE.org"}, {"vendor": "Microsoft", "product": "Microsoft Exchange Server 2016 Cumulative Update 12", "ranges": ["de 15.01.0 à 15.01.1713.010 (exclue)"], "first_unaffected": ["15.01.1713.010"], "source": "CVE.org"}, {"vendor": "Microsoft", "product": "Microsoft Exchange Server 2016 Cumulative Update 13", "ranges": ["de 15.01.0 à 15.01.1779.008 (exclue)"], "first_unaffected": ["15.01.1779.008"], "source": "CVE.org"}, {"vendor": "Microsoft", "product": "Microsoft Exchange Server 2016 Cumulative Update 14", "ranges": ["de 15.01.0 à 15.01.1847.012 (exclue)"], "first_unaffected": ["15.01.1847.012"], "source": "CVE.org"}, {"vendor": "Microsoft", "product": "Microsoft Exchange Server 2016 Cumulative Update 15", "ranges": ["de 15.01.0 à 15.01.1913.012 (exclue)"], "first_unaffected": ["15.01.1913.012"], "source": "CVE.org"}, {"vendor": "Microsoft", "product": "Microsoft Exchange Server 2016 Cumulative Update 16", "ranges": ["de 15.01.0 à 15.01.1979.008 (exclue)"], "first_unaffected": ["15.01.1979.008"], "source": "CVE.org"}, {"vendor": "Microsoft", "product": "Microsoft Exchange Server 2016 Cumulative Update 17", "ranges": ["de 15.01.0 à 15.01.2044.013 (exclue)"], "first_unaffected": ["15.01.2044.013"], "source": "CVE.org"}, {"vendor": "Microsoft", "product": "Microsoft Exchange Server 2016 Cumulative Update 18", "ranges": ["de 15.01.0 à 15.01.2106.013 (exclue)"], "first_unaffected": ["15.01.2106.013"], "source": "CVE.org"}, {"vendor": "Microsoft", "product": "Microsoft Exchange Server 2016 Cumulative Update 19", "ranges": ["de 15.01.0 à 15.01.2176.009 (exclue)"], "first_unaffected": ["15.01.2176.009"], "source": "CVE.org"}, {"vendor": "Microsoft", "product": "Microsoft Exchange Server 2016 Cumulative Update 8", "ranges": ["de 15.01.0 à 15.01.1415.010 (exclue)"], "first_unaffected": ["15.01.1415.010"], "source": "CVE.org"}, {"vendor": "Microsoft", "product": "Microsoft Exchange Server 2016 Cumulative Update 9", "ranges": ["de 15.01.0 à 15.01.1466.016 (exclue)"], "first_unaffected": ["15.01.1466.016"], "source": "CVE.org"}], "kev_name": "Microsoft Exchange Server Remote Code Execution Vulnerability", "kev_short_description": "Microsoft Exchange Server contains an unspecified vulnerability that allows for remote code execution. This vulnerability is part of the ProxyLogon exploit chain.", "kev_ransomware": "Known", "kev_notes": "Reference CISA's ED 21-02 (https://www.cisa.gov/news-events/directives/ed-21-02-mitigate-microsoft-exchange-premises-product-vulnerabilities) for further guidance and requirements. Note: The due date for addressing this vulnerability aligns with the requirements outlined in ED 21-02. https://nvd.nist.gov/vuln/detail/CVE-2021-26855", "kev_cwes": ["CWE-918"], "wordfence_id": "", "mentions_sources": [], "version_match": "unknown", "risk_score": 79, "risk_class": "Critique", "impact": {"confidentialite": "élevé", "integrite": "élevé", "disponibilite": "aucun", "summary": "Un attaquant exploitant cette vulnérabilité pourrait, selon les conditions décrites par les sources, exploitable à distance (réseau), sans authentification préalable, affecter la confidentialité des données et l'intégrité du système.", "basis": "CVSS 3.1"}, "mechanism": "Falsification de requête côté serveur (SSRF) : le serveur peut être amené à contacter des ressources internes.", "mitigation": {"correction": {"available": true, "text": "Mettre à jour : selon les sources, ne sont plus concernées les versions à partir de Microsoft Exchange Server 2013 Cumulative Update 21 15.00.1395.012, Microsoft Exchange Server 2013 Cumulative Update 22 15.00.1473.006, Microsoft Exchange Server 2013 Cumulative Update 23 15.00.1497.012, Microsoft Exchange Server 2016 Cumulative Update 10 15.01.1531.012, Microsoft Exchange Server 2016 Cumulative Update 11 15.01.1591.018."}, "mitigation": {"specific": "Aucune mesure de mitigation spécifique confirmée par les sources consultées. Consultez les références officielles pour d'éventuelles mesures détaillées.", "general": ["Maintenir le produit à jour et activer les mises à jour de sécurité.", "Restreindre l'exposition réseau du service au strict nécessaire.", "Appliquer le principe du moindre privilège.", "Surveiller les journaux et les alertes de sécurité."], "specific_links": []}, "containment": {"applicable": true, "actions": ["Action recommandée par la CISA : Apply updates per vendor instructions.", "Isoler ou restreindre l'accès au service concerné.", "Restreindre les flux réseau entrants/sortants liés au composant.", "Renforcer la surveillance des journaux et des accès.", "Désactiver temporairement le composant vulnérable si l'activité le permet."]}, "note": "Priorité aux consignes officielles de l'éditeur et des références. Vérifiez toujours l'avis de sécurité avant toute intervention en production.", "official_links": [{"url": "https://msrc.microsoft.com/update-guide/vulnerability/CVE-2021-26855", "groupe": "correctif", "groupe_titre": "Correctifs et versions corrigées", "editeur": "Microsoft", "domaine": "msrc.microsoft.com"}, {"url": "https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2021-26855", "groupe": "correctif", "groupe_titre": "Correctifs et versions corrigées", "editeur": "Microsoft", "domaine": "portal.msrc.microsoft.com"}]}, "plain": {"verdict": "now", "verdict_label": "Exploité par des attaquants · à traiter aujourd'hui", "verdict_css": "now", "verdict_rank": 0, "headline": "Le serveur peut être poussé à contacter des machines internes, à distance et sans compte", "headline_is_derived": true, "action": "Mettre à jour vers Microsoft Exchange Server 2013 Cumulative Update 21 15.00.1395.012, Microsoft Exchange Server 2013 Cumulative Update 22 15.00.1473.006 ou plus récent, version publiée comme non concernée.", "action_kind": "update", "concerned": [{"version": "Microsoft Exchange Server 2013 Cumulative Update 21 15.00.1395.012, Microsoft Exchange Server 2013 Cumulative Update 22 15.00.1473.006 ou plus récent", "state": "safe", "state_label": "Non concerné", "todo": "Rien à faire. Gardez les mises à jour automatiques activées."}, {"version": "15.00.0, 15.01.0, 15.02.0", "state": "hit", "state_label": "Concerné", "todo": "Mettre à jour vers Microsoft Exchange Server 2013 Cumulative Update 21 15.00.1395.012, Microsoft Exchange Server 2013 Cumulative Update 22 15.00.1473.006 ou plus récent, version publiée comme non concernée."}, {"version": "Je ne connais pas ma version", "state": "unknown", "state_label": "À vérifier", "todo": "La version s'affiche généralement dans le menu « À propos » ou « Aide » du logiciel."}], "steps": [{"title": "Sauvegarder avant d'intervenir", "detail": "Une copie récente des données et de la configuration. Si votre hébergeur propose une sauvegarde en un clic, c'est le moment.", "duration": "10 min", "priority": false}, {"title": "Mettre à jour vers Microsoft Exchange Server 2013 Cumulative Update 21 15.00.1395.012, Microsoft Exchange Server 2013 Cumulative Update 22 15.00.1473.006 ou plus récent, version publiée comme non concernée", "detail": "C'est la correction officielle. Tant qu'elle n'est pas appliquée, les autres mesures ne sont que temporaires.", "duration": "15 à 45 min", "priority": true}, {"title": "En attendant : réduire l'exposition sur Internet", "detail": "La faille est exploitable à distance. Limiter l'accès au service depuis l'extérieur (pare-feu, filtrage d'adresses, VPN) réduit fortement le risque.", "duration": "30 min", "priority": false}, {"title": "Vérifier que vous n'avez pas déjà été touché", "detail": "Cette faille est activement exploitée. Contrôler les comptes créés récemment, les connexions inhabituelles et les fichiers modifiés depuis la date de publication.", "duration": "30 min", "priority": true}, {"title": "Confirmer que tout fonctionne encore", "detail": "Après correction : page d'accueil, connexion, et les deux ou trois fonctions dont vous vous servez tous les jours.", "duration": "10 min", "priority": false}], "exploited": true, "exploited_label": "Oui, des attaques réelles sont constatées", "fixed_label": "Microsoft Exchange Server 2013 Cumulative Update 21 15.00.1395.012, Microsoft Exchange Server 2013 Cumulative Update 22 15.00.1473.006 (non concernée selon les sources)", "affected_label": "15.00.0, 15.01.0, 15.02.0"}, "severity_display": "Critique", "cvss_is_legacy": false, "risk_score_computable": true, "identifier": "CVE-2021-26855", "severity_fr": "Critique", "epss_pct": 100.0, "source_records": [{"source": "NVD", "label": "NVD, NIST", "date_label": "Publié dans la base", "date": "2021-03-03", "url": "https://nvd.nist.gov/vuln/detail/CVE-2021-26855"}, {"source": "CVE.org", "label": "CVE.org, programme CVE", "date_label": "Publié par l'organisme CNA", "date": "2021-03-03", "url": "https://www.cve.org/CVERecord?id=CVE-2021-26855"}, {"source": "CISA", "label": "CISA KEV", "date_label": "Ajout au catalogue", "date": "2021-11-03", "url": "https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2021-26855"}, {"source": "FIRST EPSS", "label": "FIRST EPSS", "date_label": "Score daté du", "date": "2026-10-06", "url": "https://api.first.org/data/v1/epss?cve=CVE-2021-26855"}], "exploit_public": true, "reseau_sans_auth": true, "exposition": "À distance, sans compte et sans action d'un utilisateur", "owasp": [{"code": "A01", "nom": "Contrôle d'accès défaillant", "nom_officiel": "Broken Access Control", "slug": "a01-controle-d-acces-defaillant", "libelle": "A01:2025 Contrôle d'accès défaillant", "url_officielle": "https://top10.owasp.org/2025/A01_2025-Broken_Access_Control/"}]}, "presentation": {"en_bref": [{"question": "Est-elle attaquée ?", "ton": "alerte", "reponse": "Oui, attaques constatées", "source": "Catalogue CISA KEV"}, {"question": "Existe-t-il un correctif ?", "ton": "bon", "reponse": "Oui : 15.00.1395.012, 15.00.1473.006, 15.00.1497.012, 15.01.1531.012…", "source": "Versions publiées comme non concernées"}, {"question": "Comment l'attaquer ?", "ton": "alerte", "reponse": "À distance, sans compte et sans action d'un utilisateur", "source": "Vecteur CVSS publié"}, {"question": "Risque d'exploitation", "ton": "alerte", "reponse": "100,0 % sur 30 jours", "source": "Plus probable que 100 % des failles connues"}], "references": [{"cle": "correctif", "titre": "Correctifs et versions corrigées", "explication": "Les pages que les sources désignent comme correctif ou notes de version.", "items": [{"url": "https://msrc.microsoft.com/update-guide/vulnerability/CVE-2021-26855", "domaine": "msrc.microsoft.com", "editeur": "Microsoft", "etiquettes": ["Correctif", "Avis de l'éditeur"], "nom": "", "lien": true, "casse": false}, {"url": "https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2021-26855", "domaine": "portal.msrc.microsoft.com", "editeur": "Microsoft", "etiquettes": ["Correctif", "Avis de l'éditeur"], "nom": "", "lien": true, "casse": false}]}, {"cle": "avis_tiers", "titre": "Avis d'autorités et d'organismes tiers", "explication": "CERT, agences gouvernementales, bases de vulnérabilités, chercheurs.", "items": [{"url": "https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2021-26855", "domaine": "www.cisa.gov", "editeur": "CISA", "etiquettes": ["Ressource gouvernementale américaine", "Ressource gouvernementale"], "nom": "", "lien": true, "casse": false}]}, {"cle": "exploit", "titre": "Codes d'exploitation référencés", "explication": "Les sources signalent un code d'exploitation public. Par prudence, CyberAlert affiche le site qui l'héberge sans lien direct : l'information utile ici est son existence, qui rend la faille plus facile à attaquer.", "items": [{"url": "http://packetstormsecurity.com/files/161846/Microsoft-Exchange-2019-SSRF-Arbitrary-File-Write.html", "domaine": "packetstormsecurity.com", "editeur": "Packet Storm", "etiquettes": ["Code d'exploitation", "Avis d'un tiers", "Base de vulnérabilités"], "nom": "", "lien": false, "casse": false}, {"url": "http://packetstormsecurity.com/files/161938/Microsoft-Exchange-ProxyLogon-Remote-Code-Execution.html", "domaine": "packetstormsecurity.com", "editeur": "Packet Storm", "etiquettes": ["Code d'exploitation", "Avis d'un tiers", "Base de vulnérabilités"], "nom": "", "lien": false, "casse": false}, {"url": "http://packetstormsecurity.com/files/162610/Microsoft-Exchange-2019-Unauthenticated-Email-Download.html", "domaine": "packetstormsecurity.com", "editeur": "Packet Storm", "etiquettes": ["Code d'exploitation", "Avis d'un tiers", "Base de vulnérabilités"], "nom": "", "lien": false, "casse": false}, {"url": "http://packetstormsecurity.com/files/162736/Microsoft-Exchange-ProxyLogon-Collector.html", "domaine": "packetstormsecurity.com", "editeur": "Packet Storm", "etiquettes": ["Code d'exploitation", "Avis d'un tiers", "Base de vulnérabilités"], "nom": "", "lien": false, "casse": false}]}], "liens_correction": [{"url": "https://msrc.microsoft.com/update-guide/vulnerability/CVE-2021-26855", "domaine": "msrc.microsoft.com", "editeur": "Microsoft", "etiquettes": ["Correctif", "Avis de l'éditeur"], "nom": "", "lien": true, "casse": false, "groupe": "correctif", "groupe_titre": "Correctifs et versions corrigées"}, {"url": "https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2021-26855", "domaine": "portal.msrc.microsoft.com", "editeur": "Microsoft", "etiquettes": ["Correctif", "Avis de l'éditeur"], "nom": "", "lien": true, "casse": false, "groupe": "correctif", "groupe_titre": "Correctifs et versions corrigées"}], "nb_exploits": 4, "cvss": {"version": "3.1", "vecteur": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N", "metriques": [{"code": "AV", "nom": "Vecteur d'attaque", "valeur": "Réseau (à distance, y compris par Internet)", "brut": "N", "explication": "D'où l'attaquant doit agir."}, {"code": "AC", "nom": "Complexité de l'attaque", "valeur": "Faible", "brut": "L", "explication": "Conditions hors du contrôle de l'attaquant."}, {"code": "PR", "nom": "Privilèges requis", "valeur": "Aucun (pas de compte)", "brut": "N", "explication": "Droits dont l'attaquant a besoin avant d'attaquer."}, {"code": "UI", "nom": "Interaction de l'utilisateur", "valeur": "Aucune", "brut": "N", "explication": "Une victime doit-elle cliquer ou ouvrir quelque chose ?"}, {"code": "S", "nom": "Portée", "valeur": "Inchangée", "brut": "U", "explication": "L'attaque peut-elle toucher d'autres composants que celui qui est vulnérable ?"}, {"code": "C", "nom": "Confidentialité", "valeur": "Élevé", "brut": "H", "explication": "Accès à des informations protégées."}, {"code": "I", "nom": "Intégrité", "valeur": "Élevé", "brut": "H", "explication": "Modification de données ou du système."}, {"code": "A", "nom": "Disponibilité", "valeur": "Aucun", "brut": "N", "explication": "Arrêt ou ralentissement du service."}], "calculateur": "https://www.first.org/cvss/calculator/3.1#CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N", "specification": "https://www.first.org/cvss/v3.1/specification-document"}, "cvss4": null, "cwe": [{"id": "CWE-918", "nom": "Server-Side Request Forgery (SSRF)", "url": "https://cwe.mitre.org/data/definitions/918.html"}], "owasp": [{"code": "A01", "nom": "Contrôle d'accès défaillant", "nom_officiel": "Broken Access Control", "slug": "a01-controle-d-acces-defaillant", "libelle": "A01:2025 Contrôle d'accès défaillant", "url_officielle": "https://top10.owasp.org/2025/A01_2025-Broken_Access_Control/"}], "ssvc": {"lignes": [{"nom": "Exploitation", "valeur": "Exploitation active constatée", "brut": "active"}, {"nom": "Automatisable", "valeur": "Oui : l'attaque peut être enchaînée sans intervention humaine", "brut": "yes"}, {"nom": "Impact technique", "valeur": "Total : contrôle complet du composant ou de ses informations", "brut": "total"}], "version": "2.0.3", "date": "2021-03-01", "role": "CISA Coordinator", "url": "https://www.cisa.gov/stakeholder-specific-vulnerability-categorization-ssvc"}, "chronologie": [{"date": "2021-02-08", "libelle": "Identifiant réservé", "qui": "Programme CVE"}, {"date": "2021-03-01", "libelle": "Décision SSVC publiée", "qui": "CISA"}, {"date": "2021-03-03", "libelle": "Publication de la vulnérabilité", "qui": "microsoft"}, {"date": "2021-11-03", "libelle": "Ajout au catalogue des failles exploitées", "qui": "CISA"}, {"date": "2022-05-03", "libelle": "Échéance de correction fixée par la CISA", "qui": "CISA"}, {"date": "2026-08-19", "libelle": "Dernière mise à jour de la fiche source", "qui": "Source"}, {"date": "2026-10-06", "libelle": "Calcul du score EPSS affiché", "qui": "FIRST"}], "liens_officiels": [{"nom": "NVD (NIST)", "url": "https://nvd.nist.gov/vuln/detail/CVE-2021-26855", "description": "Fiche de référence : CVSS, CPE, références étiquetées."}, {"nom": "CVE.org", "url": "https://www.cve.org/CVERecord?id=CVE-2021-26855", "description": "Enregistrement officiel publié par l'organisme qui a attribué l'identifiant."}, {"nom": "CISA KEV", "url": "https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2021-26855", "description": "Entrée du catalogue des failles activement exploitées."}, {"nom": "FIRST EPSS", "url": "https://api.first.org/data/v1/epss?cve=CVE-2021-26855", "description": "Score de probabilité d'exploitation du jour."}, {"nom": "OSV.dev", "url": "https://osv.dev/vulnerability/CVE-2021-26855", "description": "Paquets open source concernés et versions corrigées."}, {"nom": "GitHub Advisory Database", "url": "https://github.com/advisories?query=CVE-2021-26855", "description": "Avis de sécurité des dépendances logicielles."}], "produits": [{"vendor": "Microsoft", "product": "Exchange Server", "ranges": ["2013", "2016", "2019"], "first_unaffected": [], "source": "NVD"}, {"vendor": "Microsoft", "product": "Microsoft Exchange Server 2013 Cumulative Update 21", "ranges": ["de 15.00.0 à 15.00.1395.012 (exclue)"], "first_unaffected": ["15.00.1395.012"], "source": "CVE.org"}, {"vendor": "Microsoft", "product": "Microsoft Exchange Server 2013 Cumulative Update 22", "ranges": ["de 15.00.0 à 15.00.1473.006 (exclue)"], "first_unaffected": ["15.00.1473.006"], "source": "CVE.org"}, {"vendor": "Microsoft", "product": "Microsoft Exchange Server 2013 Cumulative Update 23", "ranges": ["de 15.00.0 à 15.00.1497.012 (exclue)"], "first_unaffected": ["15.00.1497.012"], "source": "CVE.org"}, {"vendor": "Microsoft", "product": "Microsoft Exchange Server 2016 Cumulative Update 10", "ranges": ["de 15.01.0 à 15.01.1531.012 (exclue)"], "first_unaffected": ["15.01.1531.012"], "source": "CVE.org"}, {"vendor": "Microsoft", "product": "Microsoft Exchange Server 2016 Cumulative Update 11", "ranges": ["de 15.01.0 à 15.01.1591.018 (exclue)"], "first_unaffected": ["15.01.1591.018"], "source": "CVE.org"}, {"vendor": "Microsoft", "product": "Microsoft Exchange Server 2016 Cumulative Update 12", "ranges": ["de 15.01.0 à 15.01.1713.010 (exclue)"], "first_unaffected": ["15.01.1713.010"], "source": "CVE.org"}, {"vendor": "Microsoft", "product": "Microsoft Exchange Server 2016 Cumulative Update 13", "ranges": ["de 15.01.0 à 15.01.1779.008 (exclue)"], "first_unaffected": ["15.01.1779.008"], "source": "CVE.org"}, {"vendor": "Microsoft", "product": "Microsoft Exchange Server 2016 Cumulative Update 14", "ranges": ["de 15.01.0 à 15.01.1847.012 (exclue)"], "first_unaffected": ["15.01.1847.012"], "source": "CVE.org"}, {"vendor": "Microsoft", "product": "Microsoft Exchange Server 2016 Cumulative Update 15", "ranges": ["de 15.01.0 à 15.01.1913.012 (exclue)"], "first_unaffected": ["15.01.1913.012"], "source": "CVE.org"}, {"vendor": "Microsoft", "product": "Microsoft Exchange Server 2016 Cumulative Update 16", "ranges": ["de 15.01.0 à 15.01.1979.008 (exclue)"], "first_unaffected": ["15.01.1979.008"], "source": "CVE.org"}, {"vendor": "Microsoft", "product": "Microsoft Exchange Server 2016 Cumulative Update 17", "ranges": ["de 15.01.0 à 15.01.2044.013 (exclue)"], "first_unaffected": ["15.01.2044.013"], "source": "CVE.org"}, {"vendor": "Microsoft", "product": "Microsoft Exchange Server 2016 Cumulative Update 18", "ranges": ["de 15.01.0 à 15.01.2106.013 (exclue)"], "first_unaffected": ["15.01.2106.013"], "source": "CVE.org"}, {"vendor": "Microsoft", "product": "Microsoft Exchange Server 2016 Cumulative Update 19", "ranges": ["de 15.01.0 à 15.01.2176.009 (exclue)"], "first_unaffected": ["15.01.2176.009"], "source": "CVE.org"}, {"vendor": "Microsoft", "product": "Microsoft Exchange Server 2016 Cumulative Update 8", "ranges": ["de 15.01.0 à 15.01.1415.010 (exclue)"], "first_unaffected": ["15.01.1415.010"], "source": "CVE.org"}, {"vendor": "Microsoft", "product": "Microsoft Exchange Server 2016 Cumulative Update 9", "ranges": ["de 15.01.0 à 15.01.1466.016 (exclue)"], "first_unaffected": ["15.01.1466.016"], "source": "CVE.org"}], "notes_kev": ["https://nvd.nist.gov/vuln/detail/CVE-2021-26855"]}, "consulted_at": "2026-10-07T14:23:26.085269+00:00"}