Reference page — cumulative record through Thursday, October 8, 2026 UTC. Reference pages update as the archive grows; only dated daily editions are immutable pages of record.
AV AC PR UI S C I A CVSS EPSS %ile KEV N L N R C H H N 9.3 .0028 18.7 —
AFFECTED Product Versions Fixed Mattermost 11.9.0 – 11.10.0
TIMELINE Jun 23 Reserved by Mattermost Sep 14 Published (CNA: Mattermost) Oct 7 RESCORED — CVE-2026-12985 (Mattermost). CVSS 6.8 → 9.3 (NVD).
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
| Date | Event | Detail |
|---|---|---|
| June 23, 2026 | Reserved | Reserved by Mattermost |
| September 14, 2026 | Published | Published (CNA: Mattermost) |
| October 7, 2026 | RESCORED | RESCORED — CVE-2026-12985 (Mattermost). CVSS 6.8 → 9.3 (NVD). |
| Vendor | Product / Package | Ecosystem | Version introduced | Fixed |
|---|---|---|---|---|
| Mattermost | Mattermost | — | 11.9.0 | 11.10.0 |
Authoritative record: CVE-2026-12985 at cve.org
Vendors: mattermost
Weaknesses: CWE-601
This is a reference page, not a dated page of record. It assembles the complete lifecycle of CVE-2026-12985 from the CVE Program record, NVD enrichment, the CISA KEV catalog, EPSS, and OSV advisories. The box score's numbers (CVSS, EPSS, KEV status) are current as of Thursday, October 8, 2026 UTC and are re-derived as the archive grows; only dated daily editions are immutable pages of record. The authoritative source for this identifier is cve.org.
