Quick answers
- Is CVE-2026-19076 exploited in the wild?
- No. Junglewise Threat Intelligence has no report of CVE-2026-19076 being exploited in the wild.
- How severe is CVE-2026-19076?
- Medium severity, with a CVSS score of 4.4, published 16 October 2026.
- Which products and versions are affected?
- Mattermost Server 11.10.0, 11.9.0-11.9.1, 11.8.0-11.8.5, 11.7.0-11.7.9.
- Is there a fix for CVE-2026-19076?
- No fixed version is recorded yet. Check the vendor's advisory in the references below. If you run it, Junglewise drafts a mitigation that fits your setup and applies it once you approve, with senior security engineers behind it.
- How is CVE-2026-19076 attacked?
- It is attacked over the network, in a web application.
- Am I affected by CVE-2026-19076?
- Check whether you run Mattermost Server at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.
Technical details
The vulnerability exists in the POST /api/v4/users/login/switch endpoint, which fails to reject OAuth application sessions during account type switching. An attacker with a valid OAuth bearer token for a target user can craft a request to this endpoint to set a password and detach the account from its identity provider, resulting in permanent account takeover. The issue affects Mattermost Server versions 11.10.x through 11.10.0, 11.9.x through 11.9.1, 11.8.x through 11.8.5, and 11.7.x through 11.7.9.
Affected products
- Mattermost Mattermost Server 11.10.0, 11.9.0-11.9.1, 11.8.0-11.8.5, 11.7.0-11.7.9
Timeline
- 2026-10-16: disclosed