CVE-2026-9699

MEDIUM

Mattermost Agents plugin logs unsanitized OpenAI API keys on authentication errors

Title source: cna
STIX 2.1

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

References (1)

Core 1
Core References
Vendor Advisory vendor-advisory
MMSA-2026-00609
https://mattermost.com/security-updates

Scores

CVSS v3 6.8
EPSS 0.0032
EPSS Percentile 24.5%
Attack Vector NETWORK
CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:C/C:H/I:N/A:N

CISA SSVC

Vulnrichment
Exploitation none
Automatable no
Technical Impact partial

Details

CWE
CWE-532
Status published
Products (7)
Mattermost/Mattermost < 10.18.11
Mattermost/Mattermost < 11.3.6
Mattermost/Mattermost < 11.6.5
Mattermost/Mattermost 10.11.19
Mattermost/Mattermost 11.5.7
Mattermost/Mattermost 11.6.4
Mattermost/Mattermost 11.7.0
Published Jun 26, 2026
Tracked Since Jun 26, 2026