Dashboard / CVE-2026-19603

CVE-2026-19603

MEDIUM
MEDIUM Priority: 0.01 BB Relevance: 59/100
Published: 2026-10-16 Modified: 2026-10-29 First seen: 2026-10-29 Status: active

Attack Surface

Network Low Complexity No Interaction

CVSS Vector Breakdown

AV: Network
AC: Low
PR: Low
UI: None
S: Unchanged
C: Low
I: None
A: None

Description

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

Weakness Classification (1)

Affected Software (1)

VendorProductVersion
mattermost mattermost_server 11.7.0 – 11.7.11

References & Advisories (1)

Bug Bounty Relevance

59 / 100
✓ Network accessible
✓ Low complexity
✓ No user interaction

CVSS Score

4.3 / 10.0 v3.1
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N

EPSS — Exploitation Probability

0.18%
Raw Score 0.001760
Percentile 7.1%
Date 2026-10-29

Intelligence Sources

nvd ref →

External Links