CVE-2026-9699

Mattermost Plugins versions <=11.6 10.18.11 11.3.6 11.6.5.0 fail to sanitize error responses from the OpenAI API before logging, which allows a user with access to server logs or support packets to obtain a valid or partially reconstructable OpenAI API key via inspection of mattermost.log entries generated during authentication failures. Mattermost Advisory ID: MMSA-2026-00609

CVSS v3 6.8 MEDIUM

6.8^/10

CVSS v3 : MEDIUM

Vector :

Exploitability : 2.3 / Impact : 4.0

Attack Vector NETWORK

Attack Complexity LOW

Privileges Required HIGH

User Interaction NONE

Confidentiality Impact HIGH

Integrity Impact NONE

Availability Impact NONE

Scope CHANGED

References

Link	Resource
https://mattermost.com/security-updates

Configurations

No configuration.

History

26 Jun 2026, 15:16

Type	Values Removed	Values Added
New CVE

Information

Published : 2026-06-26 15:16

Updated : 2026-06-26 16:16

NVD link : CVE-2026-9699

Mitre link : CVE-2026-9699

CVE.ORG link : CVE-2026-9699

JSON object : View

Products Affected

No product.

CWE

CWE-532

Insertion of Sensitive Information into Log File

{"id": "CVE-2026-9699", "cveTags": [], "metrics": {"ssvcV203": [{"source": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "ssvcData": {"id": "CVE-2026-9699", "role": "CISA Coordinator", "options": [{"exploitation": "none"}, {"automatable": "no"}, {"technicalImpact": "partial"}], "version": "2.0.3", "timestamp": "2026-06-26T15:40:45.502984Z"}}], "cvssMetricV31": [{"type": "Secondary", "source": "responsibledisclosure@mattermost.com", "cvssData": {"scope": "CHANGED", "version": "3.1", "baseScore": 6.8, "attackVector": "NETWORK", "baseSeverity": "MEDIUM", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:C/C:H/I:N/A:N", "integrityImpact": "NONE", "userInteraction": "NONE", "attackComplexity": "LOW", "availabilityImpact": "NONE", "privilegesRequired": "HIGH", "confidentialityImpact": "HIGH"}, "impactScore": 4.0, "exploitabilityScore": 2.3}]}, "affected": [{"source": "responsibledisclosure@mattermost.com", "affectedData": [{"vendor": "Mattermost", "product": "Mattermost", "versions": [{"status": "affected", "version": "0", "versionType": "semver", "lessThanOrEqual": "10.18.11"}, {"status": "affected", "version": "0", "versionType": "semver", "lessThanOrEqual": "11.3.6"}, {"status": "affected", "version": "0", "versionType": "semver", "lessThanOrEqual": "11.6.5"}, {"status": "unaffected", "version": "11.7.0"}, {"status": "unaffected", "version": "10.11.19"}, {"status": "unaffected", "version": "11.6.4"}, {"status": "unaffected", "version": "11.5.7"}], "defaultStatus": "unaffected"}]}], "published": "2026-06-26T15:16:56.083", "references": [{"url": "https://mattermost.com/security-updates", "source": "responsibledisclosure@mattermost.com"}], "vulnStatus": "Awaiting Analysis", "weaknesses": [{"type": "Secondary", "source": "responsibledisclosure@mattermost.com", "description": [{"lang": "en", "value": "CWE-532"}]}], "descriptions": [{"lang": "en", "value": "Mattermost Plugins versions <=11.6 10.18.11 11.3.6 11.6.5.0 fail to sanitize error responses from the OpenAI API before logging, which allows a user with access to server logs or support packets to obtain a valid or partially reconstructable OpenAI API key via inspection of mattermost.log entries generated during authentication failures. Mattermost Advisory ID: MMSA-2026-00609"}], "lastModified": "2026-06-26T16:16:37.360", "sourceIdentifier": "responsibledisclosure@mattermost.com"}