9.3

CVE-2026-12985

Mattermost DCR redirect URI allowlist bypass via improper URL component validation

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
Daten sind bereitgestellt durch National Vulnerability Database (NVD)
Mattermost ≫ Mattermost Server Version >= 11.7.0 < 11.7.8
Mattermost ≫ Mattermost Server Version >= 11.8.0 < 11.8.5
Mattermost ≫ Mattermost Server Version >= 11.9.0 < 11.9.1
VulnDex Vulnerability Enrichment
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Zu dieser CVE wurde keine Warnung gefunden.
EPSS Metriken
Typ Quelle Score Percentile
EPSS FIRST.org 0.28% 0.205
CVSS Metriken
Quelle Base Score Exploit Score Impact Score Vector String
NIST 9.3 2.8 5.8
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:N
responsibledisclosure@mattermost.com 6.8 1.6 5.2
CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:N
CWE-601 URL Redirection to Untrusted Site ('Open Redirect')

The web application accepts a user-controlled input that specifies a link to an external site, and uses that link in a redirect.

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