CVE-2026-4053: post edit time limit is not enforced on some post update operations

Severity: medium (CVSS 4.3 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.2% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2026-05-15 · updated 2026-06-17
Weakness: CWE-672

Description

Mattermost versions 11.5.x <= 11.5.1, 10.11.x <= 10.11.13 fail to enforce the PostEditTimeLimit on non-message post fields which allows an authenticated user to modify post file attachments, props, and pin status after the edit window has expired via the post patch and update API endpoints.. Mattermost Advisory ID: MMSA-2026-00631

Affected products

Mattermost: from 10.11.0 before 10.11.14; from 11.5.0 before 11.5.2 — fixed in 10.11.14, 11.5.2

How to fix

Upgrade to a fixed version: Mattermost 10.11.14, 11.5.2. Check the vendor advisory for mitigations.

References

https://mattermost.com/security-updates

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