CVE-2026-12985
CVE CVE-2026-12985EUVD EUVD-2026-77520Published 2026-09-14T14:09:53.000ZLast changed 2026-09-15T03:56:02.000ZCVSS 6.8
What the advisory describes
Mattermost versions 11.9.x <= 11.9.0, 11.8.x <= 11.8.4, 11.7.x <= 11.7.7 Mattermost failed to validate Dynamic Client Registration redirect URIs by URL component (matching glob patterns against the raw URI string instead) which allows a remote unauthenticated attacker to register an OAuth client with an attacker-controlled callback host that bypasses the configured redirect URI allowlist via a crafted redirect URI that places an allowlisted host/path suffix inside the query string.. Mattermost Advisory ID: MMSA-2026-00700
Source: EUVD (ENISA), in the words of the advisory.
Products the advisory names
These come from the advisory itself, not from any check we performed.
- Mattermost — Mattermost 11.8.0 ≤11.8.4; 11.9.0 ≤11.9.0; 11.7.0 ≤11.7.7
The versions shown are the advisory's own. Patchlage compares no version numbers and derives no judgement from them — which version is installed is something a person has to look up.
Carried in the product catalogue
An estate covering these products can be recorded in Patchlage. An advisory about them appears in the next morning's situation report.
- Mattermost — Mattermost
Does this concern one of your customers?
This page cannot answer that — it does not know your estate. Whoever has recorded their environments gets the answer the morning after publication, together with a paragraph they can forward to the customer unedited.
Try it for 28 daysPatchlage reports hits and suspected hits. About everything else this system says nothing — neither this page nor the situation report ever claims that an estate is safe.