Mattermost Agents plugin logs unsanitized OpenAI API keys on authentication errors

MITRE NVD CVE.ORG JSON API Print: PDF PDF

Summary

CVECVE-2026-9699
StatePUBLISHED
AssignerMattermost
Source PriorityCVE Program / NVD first with legacy fallback
Published2026-06-26 15:16:56 UTC
Updated2026-06-26 16:16:37 UTC
DescriptionMattermost 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

Risk And Classification

Primary CVSS: v3.1 6.8 MEDIUM from [email protected]

CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:C/C:H/I:N/A:N

Problem Types: CWE-532 | CWE-532 CWE-532: Insertion of Sensitive Information into Log Files

VersionSourceTypeScoreSeverityVector
3.1[email protected]Secondary6.8MEDIUMCVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:C/C:H/I:N/A:N
3.1CNACVSS6.8MEDIUMCVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:C/C:H/I:N/A:N

CVSS v3.1 Breakdown

Attack Vector
Network
Attack Complexity
Low
Privileges Required
High
User Interaction
None
Scope
Changed
Confidentiality
High
Integrity
None
Availability
None

CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:C/C:H/I:N/A:N

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA Mattermost Mattermost affected 10.18.11 semver Not specified
CNA Mattermost Mattermost affected 11.3.6 semver Not specified
CNA Mattermost Mattermost affected 11.6.5 semver Not specified
CNA Mattermost Mattermost unaffected 11.7.0 Not specified
CNA Mattermost Mattermost unaffected 10.11.19 Not specified
CNA Mattermost Mattermost unaffected 11.6.4 Not specified
CNA Mattermost Mattermost unaffected 11.5.7 Not specified

References

ReferenceSourceLinkTags
mattermost.com/security-updates [email protected] mattermost.com
CVE Program record CVE.ORG www.cve.org canonical
NVD vulnerability detail NVD nvd.nist.gov canonical, analysis

Vendor Comments And Credit

Discovery Credit

CNA: Edgar Bellot Micó (en)

Additional Advisory Data

Solutions

CNA: Update Mattermost Plugins to versions 11.7.0, 10.11.19, 11.6.4, 11.5.7 or higher.

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