CVE-2026-9699 Mattermost Agents plugin logs unsanitized OpenAI API keys on authentication errors
Attackers with log access can obtain OpenAI API keys due to unsanitized error logging in the Mattermost Agents plugin.
- Exploited in the wild
- Not known
- Login needed
- An administrator
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- None listed
What is CVE-2026-9699?
CVE-2026-9699 is a medium-severity vulnerability in Mattermost, published on 26 Jun 2026. An attacker needs administrator access to exploit it, with no action from the victim.
Official 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
Weakness: CWE-532
Which versions are affected by CVE-2026-9699?
How do I fix CVE-2026-9699?
No fix has been published for CVE-2026-9699 yet. Limit exposure of the affected software until one is available.
Is CVE-2026-9699 being exploited?
There is no known exploitation of CVE-2026-9699 in the wild and no public exploit code.
Sources
Also known as GHSA-gr4w-63r3-8h38.