{"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": "2026-07-24T19:36:26.877Z"}, "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": "2026-07-24T19:36:26.877Z"}, "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"]}}}

{}

{}

{}

{"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": "2026-07-24T01:30:03.132585+00:00", "vendors": ["microsoft", "microsoft$PRODUCT$exchange_online"]}