Skip to content
Fencer Intel
low 3.1

CVE-2025-11777 json

Cross-team channel membership access

published 11mo ago modified 23d ago also GHSA-mqcj-8c2g-h97q , GO-2025-4122 , EUVD-2025-175343

cvss
3.1
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.2%
EPSS 0.2% chance of exploitation in 30 days, percentile 9%
public exploits
0
none known

Summary

Mattermost versions 10.11.x <= 10.11.3, 10.5.x <= 10.5.11 fail to properly validate team membership permissions in the Add Channel Member API which allows users from one team to access user metadata and channel membership information from other teams via the API endpoint

Patch / fix

  • go github.com/mattermost/mattermost-server 5.3.2-0.20250905150616-ba86dfc5876b, 10.5.12, 10.5.12+incompatible, 10.11.4, 10.11.4+incompatible
  • go github.com/mattermost/mattermost/server/v8 8.0.0-20250905150616-ba86dfc5876b, 8.0.0-20251212204551-54f2e9b4afd5
  • go github.com/mattermost/mattermost 5.3.2-0.20250905150616-ba86dfc5876b
  • go github.com/mattermost/mattermost-server/v5 5.3.2-0.20250905150616-ba86dfc5876b
  • go github.com/mattermost/mattermost-server/v6 5.3.2-0.20250905150616-ba86dfc5876b
  • Mattermost Mattermost 10.5.12, 10.11.4, 11.0.0
  • govulncheck-vulndb openSUSE Leap 15.6 0.0.20251230T014957-150000.1.134.1

suse advisories SUSE-SU-2026:0037-1

  • govulncheck-vulndb openSUSE Leap 16.0 0.0.20260723T184607-160000.1.1

opensuse advisories openSUSE-SU-2026:21483-1

Is CVE-2025-11777 in your dependencies? Fencer shows which of your repositories are affected as soon as an advisory lands, and opens the fix as a pull request.

Check with Fencer

CISA SSVC

Exploitation
none
Automatable
no
Technical impact
partial
Assessed
11mo ago

Exploit prediction

0.20% chance of exploitation in the next 30 days, higher than 9% of all scored CVEs (FIRST EPSS, 2026-11-11).

CVSS scores

assigned by version score vector
CNA 3.1 3.1 CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:L/I:N/A:N
NVD 3.1 4.3 CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N
GitHub 3.1 3.1 CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:L/I:N/A:N

Affected packages

ecosystem package affected fixed in
go github.com/mattermost/mattermost-server
>=10.11.0, <10.11.4
>=10.5.0, <10.5.12
<5.3.2-0.20250905150616-ba86dfc5876b
>=10.5.0+incompatible, <10.5.12+incompatible
>=10.11.0+incompatible, <10.11.4+incompatible
10.11.4
10.5.12
5.3.2-0.20250905150616-ba86dfc5876b
10.5.12+incompatible
10.11.4+incompatible
go github.com/mattermost/mattermost/server/v8
<8.0.0-20250905150616-ba86dfc5876b
<8.0.0-20251212204551-54f2e9b4afd5
8.0.0-20250905150616-ba86dfc5876b
8.0.0-20251212204551-54f2e9b4afd5
go github.com/mattermost/mattermost
<5.3.2-0.20250905150616-ba86dfc5876b
all versions
5.3.2-0.20250905150616-ba86dfc5876b
go github.com/mattermost/mattermost-server/v5
<5.3.2-0.20250905150616-ba86dfc5876b
all versions
5.3.2-0.20250905150616-ba86dfc5876b
go github.com/mattermost/mattermost-server/v6
<5.3.2-0.20250905150616-ba86dfc5876b
all versions
5.3.2-0.20250905150616-ba86dfc5876b
go github.com/mattermost/mattermost/v5
all versions
 no fix listed

Affected products

  • Mattermost Mattermost

Classification

Weakness

References

Sources

Fencer Intel keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.