CVE-2026-18560CWE-203

CVE-2026-18560

Medium · published October 16, 2026

CVSS v3.1
4.3
EPSS
0%
Percentile
6.8
In the wild
Unconfirmed
What it is

Mattermost versions 11.10.x <= 11.10.0, 11.7.x <= 11.7.9, 11.9.x <= 11.9.1, 11.8.x <= 11.8.5 fail to validate user’s permissions before other validations which allows non-content reviewers to infer a post’s flagged status via direct API call.. Mattermost Advisory ID: MMSA-2026-00754

The record
Technical detail
CVSS v3.1
4.3 · MEDIUM
Vector
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N
CVSS v4.0
Not supplied
EPSS
0.00176 · 6.8th percentile
Weakness
CWE-203 · Observable Discrepancy
Published
2026-10-16T12:17Z
References (1)
https://mattermost.com/security-updates · [email protected]
EPSS history
Timeline
  • 17 OCT 03:28Z
    EPSS moved — → 0%
    epss
  • 16 OCT 07:10Z
    Improper order of authorisations in Mattermost GetFile API leads to an authenticated user to determine a post’s quarantined status
    cvelistv5
  • 16 OCT 07:10Z
    Improper order of authorisations in Mattermost GetFile API leads to an authenticated user to determine a post’s quarantined status
    cvelistv5