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🛡️ CVE-2026-2461 — mattermost-server

🟡 CVSS 4.3 — Medium ✅ No Known Exploit CWE-639 NVD
4.3
CVSS Score
0 Low4 Medium7 High9 Critical10

Description

Mattermost Boards Plugin fails to implement authorisation checks on comment block modifications

Mattermost Plugins versions <=11.3 11.0.3 11.2.2 10.10.11.0 fail to implement authorisation checks on comment block modifications, which allows an authorised attacker with editor permission to modify comments created by other board members. Mattermost Advisory ID: MMSA-2025-00559

How this vulnerability can be exploited

This issue can be reached over the network, attack complexity is low, an attacker needs low-level privileges on the target. No user interaction is required. The scope is unchanged, so the impact stays within the vulnerable component. Rated impact: confidentiality none, integrity low, availability none.

CVSS metrics in full

The score comes from this vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:N

  • Attack vector: Network — reachable from anywhere that can route to the service.
  • Attack complexity: Low — the attack works reliably, with no preparation.
  • Privileges required: Low — an ordinary user account is enough.
  • User interaction: None — nobody has to be tricked into anything.
  • Scope: Unchanged — the damage stays inside the vulnerable component.
  • Confidentiality impact: None.
  • Integrity impact: Low — limited, and the attacker does not choose what is affected.
  • Availability impact: None.

Weakness class

CVE-2026-2461 is classified as CWE-639: Authorization Bypass Through User-Controlled Key. An object is selected by an identifier from the request without checking the caller owns it.

Affected software

CVE-2026-2461 is recorded against 2 packages.

  • github.com/mattermost/mattermost-plugin-boards
  • mattermost-server (from 11.3.0 up to 11.3.1)

Timeline and source

Published on 16 March 2026 and last revised on 23 March 2026. No public exploit is currently recorded for this entry. A vendor advisory or fix has been published. Record sourced from NVD.

References

nvd.nist.gov (Advisory)
github.com (Web)
github.com (Package)
mattermost.com (Web)

Other advisories for this package

github.com/mattermost/mattermost-plugin-boards has other advisories on record. If you are patching this one, these are worth checking on the same host:

Same weakness in other software

These advisories are the same class of weakness (CWE-639: Authorization Bypass Through User-Controlled Key) in other software:

Details

Severity Medium
CVSS Score 4.3
CVSS Vector CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:N
CWE CWE-639
Public Exploit ✅ No
Source NVD
Published 2026-03-16
Updated 2026-08-20
Modified 2026-03-23

Affected Packages

Software From version Fixed in
github.com/mattermost/mattermost-plugin-boards
mattermost-server 11.3.0 11.3.1

Similar Threats

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