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VulnerabilityPublished

CVE-2025-11776: V8 · Mattermost fails to properly restrict access to archived channel search API

Affects github.com/mattermost/mattermost/server/v8Source GCVE Database

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Authoritative record:CVE-2025-11776· Medium 4.3

Not known to be exploited · CVSS 4.3 Medium : upgrade to 8.0.0-20250815165020-c8d66301415d when convenient.

Data as of 13 Nov 2026, 19:03 UTC

CVSS 3.1 base score
4.3Medium
How severe the flaw is on the 0–10 CVSS scale.

Thin evidence

One scorer or none
CVSS scores by source
CNA (Mattermost)CVSS 3.14.3
Patch
Available – fixed in 8.0.0-20250815165020-c8d66301415d, 5.3.2-0.20250815165020-c8d66301415d
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N

Exploitation evidence

  1. Disclosed: evidence found.

    CVE published 14 Nov 2025

  2. Detectable: no evidence on record.

    No public nuclei template indexed

  3. Weaponized: no evidence on record.

    No public exploit code indexed in Metasploit or Exploit-DB

  4. Exploited in the wild: no evidence on record.

    Not in CISA KEV and no source reports exploitation

  5. Observed by OffSeq Mirage: no evidence on record.

    No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 13 Nov 2026.

What to do

Upgrade github.com/mattermost/mattermost/server/v8 to 8.0.0-20250815165020-c8d66301415d; github.com/mattermost/mattermost and github.com/mattermost/mattermost-server and github.com/mattermost/mattermost-server/v5 and github.com/mattermost/mattermost-server/v6 to 5.3.2-0.20250815165020-c8d66301415d.

Affected software

ProductAffectedFixed in
Gogithub.com/mattermost/mattermost/server/v8Affected
  • <8.0.0-20250815165020-c8d66301415d
Fixed in
  • 8.0.0-20250815165020-c8d66301415d
Gogithub.com/mattermost/mattermostAffected
  • <5.3.2-0.20250815165020-c8d66301415d
Fixed in
  • 5.3.2-0.20250815165020-c8d66301415d
Gogithub.com/mattermost/mattermost-serverAffected
  • <5.3.2-0.20250815165020-c8d66301415d
Fixed in
  • 5.3.2-0.20250815165020-c8d66301415d
Gogithub.com/mattermost/mattermost-server/v5Affected
  • <5.3.2-0.20250815165020-c8d66301415d
Fixed in
  • 5.3.2-0.20250815165020-c8d66301415d
Gogithub.com/mattermost/mattermost-server/v6Affected
  • <5.3.2-0.20250815165020-c8d66301415d
Fixed in
  • 5.3.2-0.20250815165020-c8d66301415d

Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.

AI-suggested

A patch is available and has been released in Mattermost versions 8.0.0-20250815165020-c8d66301415d and 5.3.2-0.20250815165020-c8d66301415d. Users should upgrade to these versions or later to remediate this vulnerability.

Description

Mattermost versions prior to 8.0.0-20250815165020-c8d66301415d and 5.3.2-0.20250815165020-c8d66301415d have a vulnerability where guest users can access the archived channel search API without proper restrictions. This allows discovery of archived public channels via the /api/v4/teams/{team_id}/channels/search_archived endpoint. The issue is fixed in the specified versions.

References

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