CVE-2025-2527 | 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.

Published: 2025-05-15 Last update: 2025-08-22 Assigner: [email protected] Source: [email protected]

Conclusion & alert: CVE-2025-2527 is rated Low Risk (30.6/100): CVSS Medium severity, with low exploitation likelihood (EPSS 0.17%). Mandatory action: Monitor for updates and reassess as exploit intelligence or EPSS changes.

Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.

Exploit prediction scoring system (EPSS) score for CVE-2025-2527

EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).

# Date Old EPSS score New EPSS score Delta (New - Old)
1 2026-03-11 0.05% 0.17% +0.12%
2 2026-01-29 0.02% 0.05% +0.03%
3 2025-05-16 0.02%

Full EPSS history (3 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2025-2527

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
4.3 3.1 MEDIUM
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:L)
A normal user session is enough; they don’t have to be admin.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:L)
Some sensitive info could get out, but not a total data dump.
Integrity (I:N)
Data isn’t meaningfully altered or forged.
Availability (A:N)
Service keeps running; no real outage angle.
2.8 1.4 [email protected]

Weakness enumeration for CVE-2025-2527

GitHub Security Advisory for CVE-2025-2527

GHSA-h356-3mfw-x368 · Severity: medium · Ecosystem: go — Mattermost Fails to Verify User's Permissions When Accessing Groups

Affected software / configurations for CVE-2025-2527

Vendor Product Version Raw CPE
mattermost mattermost_server >= 9.11.0, < 9.11.12 cpe:2.3:a:mattermost:mattermost_server:*:*:*:*:*:*:*:*
mattermost mattermost_server >= 10.5.0, < 10.5.3 cpe:2.3:a:mattermost:mattermost_server:*:*:*:*:*:*:*:*

References for CVE-2025-2527

URL Tags
https://mattermost.com/security-updates Vendor Advisory
cvelogic Threat Intelligence