CVE-2026-19603

mediumpriority · track · 0EPSS 0.002 · 7 %ileDE
grimoire priorityP3 · Track
Exploitable?
—
no known exploitation
Likely / severe?
0.18% (7th) EPSS
CVSS 4.3 · medium
Is it mine?
10 products
Check your exposure
Who says so?
1 sources
cert_bund

EPSS · scored 2026-10-27

Mattermost versions 11.9.x <= 11.9.1, 11.8.x <= 11.8.5, 11.7.x <= 11.7.10, 11.10.x <= 11.10.1 fail to sanitize the active channel field returned by the user status API endpoints, which allows an authenticated user to learn the channel ID of a private channel another user is actively viewing via the status endpoints, without being a member of that channel. Mattermost Advisory ID: MMSA-2026-00765

01

cvss

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

4.3
010

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

v3.14.3mediumCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:Nsecondary · responsibledisclosure@mattermost.comexploitability 2.8 · impact 1.4
v3.14mediumCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N/E:Usecondary · CVSS-BT (t0sche)
02

ssvc

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

Trackcoordinatorcisa_ssvcUS
03

weaknesses

The CWE weakness classes this flaw belongs to.

CWE-201US
04

affected products (10)

Products and version ranges known to be affected.

05

advisories (1)

Vendor and ecosystem advisories describing this.

  • WID-SEC-W-2026-4009Mattermost: Mehrere SchwachstellenDeutsch2026-10-15csaf · cert_bundDE

    Ein Angreifer kann mehrere Schwachstellen in Mattermost ausnutzen, um Sicherheitsvorkehrungen zu umgehen, um seine Privilegien zu erhöhen, um einen Denial of Service Angriff durchzuführen, um Informationen offenzulegen, um Dateien zu manipulieren.

06

sources

Which sources assert this record, and when.

cert_bundNVDCVE.orgMITRE
published 2026-10-16modified 2026-10-16
07

references (1) nvd

External citations — patches, advisories, analysis.

scry

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