CVE-2026-9699

Mattermost Agents plugin logs unsanitized OpenAI API keys on authentication errors

State: Published
Severity: 6.8 Medium
Published: Jun 26, 2026
Updated: Jun 26, 2026
Reserved: May 27, 2026

Description

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

Scores

CVSS	Score	Vector	Source
3.1	6.8 Medium	CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:C/C:H/I:N/A:N	Mattermost

Weaknesses

CWE-532 Insertion of Sensitive Information into Log Files

Affected Products

Product	Versions
MattermostMattermost	10.18.11 and earlierAffected 11.3.6 and earlierAffected 11.6.5 and earlierAffected 11.7.0Not affected 10.11.19Not affected 11.6.4Not affected 11.5.7Not affected

References

MMSA-2026-00609vendor-advisory

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