CVE-2026-56191

{"dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": {"cveId": "CVE-2026-56191", "assignerOrgId": "f38d906d-7342-40ea-92c1-6c4a2c6478c8", "state": "PUBLISHED", "assignerShortName": "microsoft", "dateReserved": "2026-06-19T13:54:04.006Z", "datePublished": "2026-07-24T00:01:12.361Z", "dateUpdated": "2026-11-10T22:41:08.340Z"}, "containers": {"cna": {"title": "Microsoft Exchange Online Tampering Vulnerability", "datePublic": "2026-07-23T14:00:00.000Z", "cpeApplicability": [{"nodes": [{"operator": "OR", "negate": false, "cpeMatch": [{"vulnerable": true, "criteria": "cpe:2.3:a:microsoft:exchange_online:*:*:*:*:*:*:*:*", "versionStartIncluding": "-"}]}]}], "affected": [{"vendor": "Microsoft", "product": "Microsoft Exchange Online", "versions": [{"version": "-", "status": "affected"}]}], "descriptions": [{"value": "Improper authentication in Microsoft Exchange Online allows an unauthorized attacker to perform tampering over a network.", "lang": "en-US"}], "problemTypes": [{"descriptions": [{"description": "CWE-287: Improper Authentication", "lang": "en-US", "type": "CWE", "cweId": "CWE-287"}]}], "providerMetadata": {"orgId": "f38d906d-7342-40ea-92c1-6c4a2c6478c8", "shortName": "microsoft", "dateUpdated": "2026-11-10T22:41:08.340Z"}, "references": [{"name": "Microsoft Exchange Online Tampering Vulnerability", "tags": ["vendor-advisory", "patch"], "url": "https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-56191"}], "metrics": [{"format": "CVSS", "scenarios": [{"lang": "en-US", "value": "GENERAL"}], "cvssV3_1": {"version": "3.1", "baseSeverity": "CRITICAL", "baseScore": 10, "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H/E:U/RL:O/RC:C"}}], "tags": ["exclusively-hosted-service"]}, "adp": [{"metrics": [{"other": {"type": "ssvc", "content": {"timestamp": "2026-07-24T00:00:00+00:00", "options": [{"Exploitation": "none"}, {"Automatable": "yes"}, {"Technical Impact": "total"}], "role": "CISA Coordinator", "version": "2.0.3", "id": "CVE-2026-56191"}}}], "title": "CISA ADP Vulnrichment", "providerMetadata": {"orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "shortName": "CISA-ADP", "dateUpdated": "2026-07-25T03:55:27.486Z"}}]}}

{"dataType": "CVE_RECORD", "containers": {"adp": [{"title": "CISA ADP Vulnrichment", "metrics": [{"other": {"type": "ssvc", "content": {"id": "CVE-2026-56191", "role": "CISA Coordinator", "options": [{"Exploitation": "none"}, {"Automatable": "yes"}, {"Technical Impact": "total"}], "version": "2.0.3", "timestamp": "2026-07-24T22:09:02.842776Z"}}}], "providerMetadata": {"orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "shortName": "CISA-ADP", "dateUpdated": "2026-07-24T22:09:07.842Z"}}], "cna": {"tags": ["exclusively-hosted-service"], "title": "Microsoft Exchange Online Tampering Vulnerability", "metrics": [{"format": "CVSS", "cvssV3_1": {"version": "3.1", "baseScore": 10, "baseSeverity": "CRITICAL", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H/E:U/RL:O/RC:C"}, "scenarios": [{"lang": "en-US", "value": "GENERAL"}]}], "affected": [{"vendor": "Microsoft", "product": "Microsoft Exchange Online", "versions": [{"status": "affected", "version": "-"}]}], "datePublic": "2026-07-23T14:00:00.000Z", "references": [{"url": "https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-56191", "name": "Microsoft Exchange Online Tampering Vulnerability", "tags": ["vendor-advisory", "patch"]}], "descriptions": [{"lang": "en-US", "value": "Improper authentication in Microsoft Exchange Online allows an unauthorized attacker to perform tampering over a network."}], "problemTypes": [{"descriptions": [{"lang": "en-US", "type": "CWE", "cweId": "CWE-287", "description": "CWE-287: Improper Authentication"}]}], "cpeApplicability": [{"nodes": [{"negate": false, "cpeMatch": [{"criteria": "cpe:2.3:a:microsoft:exchange_online:*:*:*:*:*:*:*:*", "vulnerable": true, "versionStartIncluding": "-"}], "operator": "OR"}]}], "providerMetadata": {"orgId": "f38d906d-7342-40ea-92c1-6c4a2c6478c8", "shortName": "microsoft", "dateUpdated": "2026-11-10T22:41:08.340Z"}}}, "cveMetadata": {"cveId": "CVE-2026-56191", "state": "PUBLISHED", "dateUpdated": "2026-11-10T22:41:08.340Z", "dateReserved": "2026-06-19T13:54:04.006Z", "assignerOrgId": "f38d906d-7342-40ea-92c1-6c4a2c6478c8", "datePublished": "2026-07-24T00:01:12.361Z", "assignerShortName": "microsoft"}, "dataVersion": "5.2"}

{"affected": [{"affectedData": [{"product": "Microsoft Exchange Online", "vendor": "Microsoft", "versions": [{"status": "affected", "version": "-"}]}], "source": "secure@microsoft.com"}], "configurations": [{"nodes": [{"cpeMatch": [{"criteria": "cpe:2.3:a:microsoft:exchange_online:-:*:*:*:*:*:*:*", "matchCriteriaId": "DA6C3728-2BB2-4BA9-BB20-D784F18AD402", "vulnerable": true}], "negate": false, "operator": "OR"}]}], "cveTags": [{"sourceIdentifier": "secure@microsoft.com", "tags": ["exclusively-hosted-service"]}], "descriptions": [{"lang": "en", "value": "Improper authentication in Microsoft Exchange Online allows an unauthorized attacker to perform tampering over a network."}, {"lang": "es", "value": "Autenticaci\u00f3n indebida en Microsoft Exchange Online permite a un atacante no autorizado realizar manipulaciones a trav\u00e9s de una red."}], "id": "CVE-2026-56191", "lastModified": "2026-10-24T13:10:00.147", "metrics": {"cvssMetricV31": [{"cvssData": {"attackComplexity": "LOW", "attackVector": "NETWORK", "availabilityImpact": "HIGH", "baseScore": 10.0, "baseSeverity": "CRITICAL", "confidentialityImpact": "HIGH", "integrityImpact": "HIGH", "privilegesRequired": "NONE", "scope": "CHANGED", "userInteraction": "NONE", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H", "version": "3.1"}, "exploitabilityScore": 3.9, "impactScore": 6.0, "source": "secure@microsoft.com", "type": "Secondary"}], "ssvcV203": [{"source": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "ssvcData": {"id": "CVE-2026-56191", "options": [{"exploitation": "none"}, {"automatable": "yes"}, {"technicalImpact": "total"}], "role": "CISA Coordinator", "timestamp": "2026-07-24T00:00:00+00:00", "version": "2.0.3"}}]}, "published": "2026-07-24T01:17:36.417", "references": [{"source": "secure@microsoft.com", "tags": ["Vendor Advisory"], "url": "https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-56191"}], "sourceIdentifier": "secure@microsoft.com", "vulnStatus": "Analyzed", "weaknesses": [{"description": [{"lang": "en", "value": "CWE-287"}], "source": "secure@microsoft.com", "type": "Secondary"}]}

{}

{"affected": [{"configurations": [{"platform": null, "status": "affected", "versions": {"scheme": "generic", "value": "[0,*]"}}], "enrichment": {"confidence": 95.0, "confidence_source": "inferred", "scores": [{"score": 95.0, "source": "inferred"}, {"score": 100.0, "source": "matching"}]}, "original": {"product": "Microsoft Exchange Online", "source": "cna", "vendor": "Microsoft"}, "product": "exchange_online", "vendor": "microsoft"}], "created": "2026-07-24T01:30:03.132543+00:00", "updated": "2026-08-03T21:00:12.497820+00:00", "vendors": ["microsoft", "microsoft$PRODUCT$exchange_online"]}