CVE-2025-2527

Improper access control to group information

4.3 MediumFix available

Mattermost versions 10.5.x <= 10.5.2, 9.11.x <= 9.11.11 failed to properly verify a user's permissions when accessing groups, which allows an attacker to view group information via an API request.

Attack profile

How easy it is to exploit

Attack vector: Network
Complexity: Low
Privileges needed: Low
User interaction: None

What an attacker can affect

Confidentiality: Low
Integrity: None
Availability: None

Exploit likelihood

0.31%Up 0.3 points since May 16, 2025

What each source reports

CVE List Score used 4.3

Improper access control to group information

Mattermost versions 10.5.x <= 10.5.2, 9.11.x <= 9.11.11 failed to properly verify a user's permissions when accessing groups, which allows an attacker to view group information via an API request.

Record: CVE-2025-2527
CVSS 3.1: 4.3 MediumCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N
Weakness: CWE-863
Updated: 2026-11-02

EUVDEUVD-2025-15177 4.3

Mattermost versions 10.5.x <= 10.5.2, 9.11.x <= 9.11.11 failed to properly verify a user's permissions when accessing groups, which allows an attacker to view group information via an API request.

Record: EUVD-2025-15177
CVSS 3.1: 4.3 MediumCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N
Updated: 2026-11-02

GitHub AdvisoriesGHSA-h356-3mfw-x368 4.3

Mattermost Fails to Verify User's Permissions When Accessing Groups

Mattermost versions 10.5.x <= 10.5.2, 9.11.x <= 9.11.11 failed to properly verify a user's permissions when accessing groups, which allows an attacker to view group information via an API request.

Record: GHSA-h356-3mfw-x368
CVSS 3.1: 4.3 MediumCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N
Weakness: CWE-863
Updated: 2026-11-02

NVD 4.3

Mattermost versions 10.5.x <= 10.5.2, 9.11.x <= 9.11.11 failed to properly verify a user's permissions when accessing groups, which allows an attacker to view group information via an API request.

Record: CVE-2025-2527
CVSS 3.1: 4.3 MediumCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N
Weakness: CWE-863
Updated: 2026-11-02

OSV 4.3

Improper access control to group information

Mattermost versions 10.5.x <= 10.5.2, 9.11.x <= 9.11.11 failed to properly verify a user's permissions when accessing groups, which allows an attacker to view group information via an API request.

Record: CVE-2025-2527
CVSS 3.1: 4.3 MediumCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N
Weakness: CWE-863
Updated: 2026-11-02

OSVGHSA-h356-3mfw-x368 4.3

Mattermost Fails to Verify User's Permissions When Accessing Groups

Mattermost versions 10.5.x <= 10.5.2, 9.11.x <= 9.11.11 failed to properly verify a user's permissions when accessing groups, which allows an attacker to view group information via an API request.

Record: GHSA-h356-3mfw-x368
CVSS 3.1: 4.3 MediumCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N
Weakness: CWE-863
Updated: 2026-11-02

OSVGO-2025-3691 No score

Mattermost Fails to Verify User's Permissions When Accessing Groups in github.com/mattermost/mattermost-server

Mattermost Fails to Verify User's Permissions When Accessing Groups in github.com/mattermost/mattermost-server

Record: GO-2025-3691
Updated: 2026-11-02

OSVopenSUSE-SU-2025:15159-1 No score

govulncheck-vulndb-0.0.20250523T151856-1.1 on GA media

These are all security issues fixed in the govulncheck-vulndb-0.0.20250523T151856-1.1 package on the GA media of openSUSE Tumbleweed.

Record: openSUSE-SU-2025:15159-1
Updated: 2026-11-02

Affected products

Affected packages

Affected packages
Package	Affected	Fixed
`github.com/mattermost/mattermost/server/v8` Go	10.5.0 to 10.5.2	10.5.3
`github.com/mattermost/mattermost/server/v8` Go	9.11.0 to 9.11.11	9.11.12
`github.com/mattermost/mattermost/server/v8` Go	before 8.0.0-20250411064244-844447fbd57c	8.0.0-20250411064244-844447fbd57c
`github.com/mattermost/mattermost/server/v8` Go	10.5.0 up to 10.5.3	10.5.3
`github.com/mattermost/mattermost/server/v8` Go	9.11.0 up to 9.11.12	9.11.12
`github.com/mattermost/mattermost-server` Go	9.11.0+incompatible up to 9.11.12+incompatible, 10.5.0+incompatible up to 10.5.3+incompatible	9.11.12+incompatible10.5.3+incompatible
`github.com/mattermost/mattermost-server/v5` Go	All versions	None known
`github.com/mattermost/mattermost-server/v6` Go	All versions	None known
`govulncheck-vulndb` openSUSE:Tumbleweed From an advisory covering 14 CVEs	before 0.0.20250523T151856-1.1	0.0.20250523T151856-1.1

History

History
Recorded	Changed	Sources
Nov 6, 2026	affected, facts
Nov 2, 2026	first indexed	CVE List, EUVD, GitHub Advisories, NVD, OSV

Dates are when Every CVE recorded each change. Upstream dates may differ.

In short

CVE-2025-2527 is a medium vulnerability (CVSS 4.3) in Mattermost, published May 15, 2025. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 0.31%, the 24th percentile. Fixed in github.com/mattermost/mattermost/server/v8 10.5.3.

References

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