4.3

CVE-2025-11776: mattermost Incorrect Authorization

CVSS: 4.3v3.1MediumAnalyzed
AliasesGHSA-j6gg-r5jc-47cmGO-2025-4126
Published 14-11-2025Last modified 14-11-2025
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Vulnerability summary

CVE-2025-11776 is a medium (CVSS 4.3) Incorrect Authorization vulnerability in mattermost. EPSS estimates a 0.21% chance of exploitation in the next 30 days, higher than 10.2% of scored vulnerabilities.

Overall risk
17/100
0100
Low · default modelHow is this calculated?
CVSS score
4.3/10
010
Medium · v3.1 (CVE.org)
EPSS score
0.21%
0%100%
Low · +0.02 pp in 30 days
KEVNot listedIn no KEV catalog
RansomwareNone recordedNo known use recorded
Public exploits0No public exploits recorded

Advisory lineage

Upstream 0 · Downstream 1 · Related 1
OPENSUSE-SU-2026:21483-1

Timeline

  1. 14-11-2025
    PublishedVulnerability first disclosed.
  2. 14-11-2025
    Last modifiedVulnerability information updated.

Description

Mattermost versions <11 fail to properly restrict access to archived channel search API which allows guest users to discover archived public channels via the `/api/v4/teams/{team_id}/channels/search_archived` endpoint

CVSS metrics

3 scores · 3 sources · 1 version

EPSS trend

Probability

0.21%

Chance of exploitation in the next 30 days

Percentile

10%

Versus all other CVEs

30-day change

+0.02 pp

From 0.19% on 20-09-2026

20-09-202620-10-2026
EPSS score
0.21%

Known exploited

Compare KEV catalogs

Not in any of the 3 tracked catalogs.

Public exploits

0 found

No public exploits indexed.

Weaknesses

CWE · root cause

Affected systems

Github.com/mattermost2 products
  • mattermost< 5.3.2-0.20250815165020-c8d66301415d | All versions (No fix recorded)
  • mattermost-server< 5.3.2-0.20250815165020-c8d66301415d | All versions (No fix recorded)
Github.com/mattermost/mattermost-server2 products
  • v5< 5.3.2-0.20250815165020-c8d66301415d | All versions (No fix recorded)
  • v6< 5.3.2-0.20250815165020-c8d66301415d | All versions (No fix recorded)
Mattermost2 products
Github.com/mattermost/mattermost1 product
  • v5All versions (No fix recorded)
Github.com/mattermost/mattermost/server1 product
  • v8< 8.0.0-20250815165020-c8d66301415d

5 vendors · 8 products

References

4 links