CVE-2026-2458

CWE-862 — Missing Authorization6 documents5 sources
Severity
4.3MEDIUM
EPSS
0.0%
top 91.53%
CISA KEV
Not in KEV
Exploit
No known exploits
Affected products
4
Github.com Mattermost/mattermost-serverGithub.com Mattermost/mattermost/server/v8Mattermost Mattermost Server+1 more
Timeline
PublishedMar 16
Latest updateMar 23

Description

Mattermost versions 11.3.x <= 11.3.0, 11.2.x <= 11.2.2, 10.11.x <= 10.11.10 fail to properly validate team membership when searching channels which allows a removed team member to enumerate all public channels within a private team via the channel search API endpoint.. Mattermost Advisory ID: MMSA-2025-00568

CVSS vector

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:NExploitability: 2.8 | Impact: 1.4

Affected Packages4 packages

▶NVDmattermost/mattermost_server10.11.0 — 10.11.11+2
▶Gogithub.com/mattermost/mattermost-server10.11.0-rc1+incompatible — 10.11.11+incompatible+6
▶Gogithub.com/mattermost/mattermost/server/v8< 8.0.0-20260113182106-a18b80ba4c32
▶CVEListV5mattermost/mattermost11.3.0 — 11.3.0+2

🔴Vulnerability Details

4
OSV
Mattermost allows a removed team member to enumerate all public channels within a private team in github.com/mattermost/mattermost-server↗2026-03-23
▶
OSV
Mattermost allows a removed team member to enumerate all public channels within a private team↗2026-03-16
▶
CVEList
Unauthorized channel enumeration in private teams after member removal↗2026-03-16
▶
GHSA
Mattermost allows a removed team member to enumerate all public channels within a private team↗2026-03-16
▶

🕵️Threat Intelligence

1
Wiz
CVE-2026-2458 Impact, Exploitability, and Mitigation Steps | Wiz↗
▶
CVE-2026-2458 (MEDIUM CVSS 4.3) | Mattermost versions 11.3.x <= 11.3. | cvebase.io