Vulnerability · Published May 15, 2026 · Assigned by Mattermost

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

Low 3.1

In plain English

A low-severity security flaw in Mattermost from Mattermost. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.2% (higher than 6% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.

Severity (CVSS 3.1)3.1Low

Exploit odds (30 days)0.2%top 94.3% of all CVEs

Exploited in the wildNo reportsCISA SSVC: none

Attack toolingNoneno public tooling known

Official 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 packages & fixed versions

Ecosystem	Package	Fixed in	Advisory
Go	github.com/mattermost/mattermost-server	11.5.2	GHSA-hw87-6jcq-9f8q
Go	github.com/mattermost/mattermost-server	0.0.0-20260414103857-b21ef302025e	GHSA-hw87-6jcq-9f8q
Go	github.com/mattermost/mattermost-server	0.0.0-20260414103857-b21ef302025e, 11.5.2+incompatible	GO-2026-5442

Affected products (as reported)

Vendor	Product	Versions
Mattermost	Mattermost	11.5.0 – through 11.5.110.11.0 – through 10.11.13

Weakness: CWE-672 · Vector: CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:N/I:L/A:N

References

MMSA-2026-00631 vendor-advisory