CVE-2025-12689

mediumpriority · track · 0EPSS 0.003 · 21 %ileDEEUUS

grimoire priorityP3 · Track

Exploitable?

—

no known exploitation

Likely / severe?

0.29% (21st) EPSS

CVSS 6.5 · medium

Is it mine?

23 products

Check your exposure

Who says so?

5 sources

cnnvd · enisa_euvd · osv · cert_bund

EPSS · scored 2026-10-27

Mattermost versions 11.0.x <= 11.0.4, 10.12.x <= 10.12.2, 10.11.x <= 10.11.6 fail to check WebSocket request field for proper UTF-8 format, which allows attacker to crash Calls plug-in via sending malformed request.

cvss

Technical severity, 0–10. One row per scoring source.

6.5

010

base score 0–10 · higher = more severe · hover a vector to decode

v3.16.5mediumCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:Hsecondary · ENISA EU

v3.16.5mediumCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:Hsecondary · responsibledisclosure@mattermost.comexploitability 2.8 · impact 3.6

v3.16.5mediumCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:Hsecondary · OSV

v3.16mediumCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H/E:Usecondary · CVSS-BT (t0sche)

ssvc

A stakeholder decision — act, attend, or track — from exploitation and impact.

Trackcoordinatorcisa_ssvcUS

weaknesses

The CWE weakness classes this flaw belongs to.

CWE-1287USCWE-1287US

affected products (23)

Products and version ranges known to be affected.

Mattermost Mattermost Server <10.11.7all versionscert_bundDE
Mattermost Mattermost Server <10.11.9all versionscert_bundDE
Mattermost Mattermost Server <10.12.3all versionscert_bundDE
Mattermost Mattermost Server <11.0.5all versionscert_bundDE
Mattermost Mattermost Server <11.0.7all versionscert_bundDE
Mattermost Mattermost Server <11.1.0all versionscert_bundDE
Mattermost Mattermost Server <11.1.2all versionscert_bundDE
Mattermost Mattermost Server <11.2.0all versionscert_bundDE
Mattermost Mattermost≤ Server <11.0.5cert_bundDE
Mattermost Mattermost≤ Server <10.11.7cert_bundDE
Mattermost Mattermost≤ Server <10.11.9cert_bundDE
Mattermost Mattermost≤ Server <10.12.3cert_bundDE
Mattermost Mattermost≤ Server <11.0.7cert_bundDE
Mattermost Mattermost≤ Server <11.1.0cert_bundDE
Mattermost Mattermost≤ Server <11.1.2cert_bundDE
Mattermost Mattermost≤ Server <11.2.0cert_bundDE
Mattermost Mattermost≤ 10.12.0 ≤10.12.2enisa_euvdEU
Mattermost Mattermost≤ 10.11.0 ≤10.11.6enisa_euvdEU
Mattermost Mattermost≤ 11.0.0 ≤11.0.4enisa_euvdEU
mattermost mattermost server10.11.0 → 10.11.7nvdUScpe:2.3:a:mattermost:mattermost_server:*:*:*:*:*:*:*:*

showing 20 of 23

advisories (3)

Vendor and ecosystem advisories describing this.

WID-SEC-W-2025-2880Mattermost Server und Desktop: Mehrere SchwachstellenDeutsch2025-12-17csaf · cert_bundDE
Ein Angreifer kann mehrere Schwachstellen in Mattermost Server und Desktop ausnutzen, um Informationen offenzulegen, Sicherheitsmechanismen zu umgehen und um einen Denial of Service Zustand herbeizuführen.
GHSA-j5vq-62gr-8v3rMattermost fails to check Websocket request for proper UTF-8 format potentially crashing Calls plug-in2025-12-17ghsa · osvUS
Mattermost versions 11.0.x <= 11.0.4, 10.12.x <= 10.12.2, 10.11.x <= 10.11.6 fail to check WebSocket request field for proper UTF-8 format, which allows attacker to crash Calls plug-in via sending malformed request.
GO-2025-4255Mattermost fails to check Websocket request for proper UTF-8 format potentially crashing Calls plug-in in github.com/mattermost/mattermost-plugin-calls2025-12-30vendor · osvUS
Mattermost fails to check Websocket request for proper UTF-8 format potentially crashing Calls plug-in in github.com/mattermost/mattermost-plugin-calls

also known as (5)

Other names and identifiers for this entity.

sources

Which sources assert this record, and when.

cnnvd enisa_euvd osv cert_bund nvd NVD CVE.org MITRE

published 2025-12-17modified 2026-10-13

references (4)

External citations — patches, advisories, analysis.

scry

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