CVE-2026-12985
6.8
CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:N
Summary
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 Software
| Vendor | Product | Version Range | Status |
|---|---|---|---|
| Mattermost | Mattermost | 11.9.0 <= 11.9.0 | affected |
| Mattermost | Mattermost | 11.8.0 <= 11.8.4 | affected |
| Mattermost | Mattermost | 11.7.0 <= 11.7.7 | affected |
| Mattermost | Mattermost | 11.10.0 | unaffected |
| Mattermost | Mattermost | 11.9.1 | unaffected |
| Mattermost | Mattermost | 11.8.5 | unaffected |
| Mattermost | Mattermost | 11.7.8 | unaffected |
Weaknesses
- CWE-601: CWE-601: URL Redirection to Untrusted Site (“Open Redirect”)
ADP Enrichment
CISA ADP Vulnrichment
- SSVC:
- Exploitation: none
- Automatable: no
- Technical Impact: total
References
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