CVEvulnerability

CVE-2026-12985

9.3 CRITICAL Published 2026-09-14 Modified 2026-10-07 Official page ↗
Status
Analyzed
Published
2026-09-14
Last modified
2026-10-07
Assigner
[email protected]
CVSS 3.1 ([email protected])
6.8 MEDIUM — CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:N
CVSS 3.1 ([email protected])
9.3 CRITICAL — CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:N
Weaknesses
CWE-601

Description

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

Affected configurations

• mattermost mattermost server (>= 11.7.0 < 11.7.8) • mattermost mattermost server (>= 11.8.0 < 11.8.5) • mattermost mattermost server (>= 11.9.0 < 11.9.1)

Related

Weakness · CWE (1)

  • CWE-601 URL Redirection to Untrusted Site weakness

References