What is CVE-2026-1629?

CVE-2026-1629 is a medium-severity vulnerability in Mattermost, classified under Operation on a Resource after Expiration or Release. CVSS score: 4.3/10. Published 2026-03-16.

How severe is CVE-2026-1629?

Medium severity. CVSS v3 base score is 4.3 out of 10.

Vulnerability in Mattermost

CVE-2026-1629

Mattermost versions 10.11.x <= 10.11.10 Fail to invalidate cached permalink preview data when a user loses channel access which allows the user to continue viewing private channel content via previously cached permalink previews until cache reset or relogin.. Mattermost Advisory ID: MMSA-2026-00580

Published 2026-03-16 · last modified 2026-06-17.

CVSS v3 metric

CVSS v3 base score 4.3 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N.

EPSS exploit prediction

EPSS: 0.002 (9.3th percentile), scored 2026-10-01.

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 9th percentile — 9.3% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.002 · newest: 0.002 · change: 0.000

Affected products

Mattermost — versions 10.11.0, 11.4.0, 10.11.11
Mattermost Server

Weakness classification (CWE)

CWE-672 — Operation on a Resource after Expiration or Release

References

mattermost.com/security-updates (vendor-advisory, Vendor Advisory)

Frequently asked questions

What is CVE-2026-1629?: CVE-2026-1629 is a medium-severity vulnerability in Mattermost, classified under Operation on a Resource after Expiration or Release. CVSS score: 4.3/10. Published 2026-03-16.
How severe is CVE-2026-1629?: Medium severity. CVSS v3 base score is 4.3 out of 10.