{"dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": {"cveId": "CVE-2026-26164", "assignerOrgId": "f38d906d-7342-40ea-92c1-6c4a2c6478c8", "state": "PUBLISHED", "assignerShortName": "microsoft", "dateReserved": "2026-02-11T18:33:57.776Z", "datePublished": "2026-05-07T20:58:09.538Z", "dateUpdated": "2026-05-07T20:58:09.538Z"}, "containers": {"cna": {"title": "M365 Copilot Information Disclosure Vulnerability", "datePublic": "2026-05-07T14:00:00.000Z", "cpeApplicability": [{"nodes": [{"operator": "OR", "negate": false, "cpeMatch": [{"vulnerable": true, "criteria": "cpe:2.3:a:microsoft:365_copilot_business_chat:*:*:*:*:*:*:*:*", "versionStartIncluding": "-"}]}]}], "affected": [{"vendor": "Microsoft", "product": "Microsoft 365 Copilot's Business Chat", "versions": [{"version": "-", "status": "affected"}]}], "descriptions": [{"value": "Improper neutralization of special elements in output used by a downstream component ('injection') in M365 Copilot allows an unauthorized attacker to disclose information over a network.", "lang": "en-US"}], "problemTypes": [{"descriptions": [{"description": "CWE-74: Improper Neutralization of Special Elements in Output Used by a Downstream Component ('Injection')", "lang": "en-US", "type": "CWE", "cweId": "CWE-74"}]}], "providerMetadata": {"orgId": "f38d906d-7342-40ea-92c1-6c4a2c6478c8", "shortName": "microsoft", "dateUpdated": "2026-05-07T20:58:09.538Z"}, "references": [{"name": "M365 Copilot Information Disclosure Vulnerability", "tags": ["vendor-advisory", "patch"], "url": "https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-26164"}], "metrics": [{"format": "CVSS", "scenarios": [{"lang": "en-US", "value": "GENERAL"}], "cvssV3_1": {"version": "3.1", "baseSeverity": "HIGH", "baseScore": 7.5, "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N/E:U/RL:O/RC:C"}}], "tags": ["exclusively-hosted-service"]}}}

{}

{"cveTags": [{"sourceIdentifier": "secure@microsoft.com", "tags": ["exclusively-hosted-service"]}], "descriptions": [{"lang": "en", "value": "Improper neutralization of special elements in output used by a downstream component ('injection') in M365 Copilot allows an unauthorized attacker to disclose information over a network."}], "id": "CVE-2026-26164", "lastModified": "2026-05-07T22:16:33.773", "metrics": {"cvssMetricV31": [{"cvssData": {"attackComplexity": "LOW", "attackVector": "NETWORK", "availabilityImpact": "NONE", "baseScore": 7.5, "baseSeverity": "HIGH", "confidentialityImpact": "HIGH", "integrityImpact": "NONE", "privilegesRequired": "NONE", "scope": "UNCHANGED", "userInteraction": "NONE", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N", "version": "3.1"}, "exploitabilityScore": 3.9, "impactScore": 3.6, "source": "secure@microsoft.com", "type": "Primary"}]}, "published": "2026-05-07T22:16:33.773", "references": [{"source": "secure@microsoft.com", "url": "https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-26164"}], "sourceIdentifier": "secure@microsoft.com", "vulnStatus": "Received", "weaknesses": [{"description": [{"lang": "en", "value": "CWE-74"}], "source": "secure@microsoft.com", "type": "Primary"}]}

{}

{"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 365 Copilot's Business Chat", "source": "cna", "vendor": "Microsoft"}, "product": "365_copilot_business_chat", "vendor": "microsoft"}], "created": "2026-05-07T22:30:36.248437+00:00", "updated": "2026-05-08T00:00:11.978134+00:00", "vendors": ["microsoft", "microsoft$PRODUCT$365_copilot_business_chat"]}