GHSA-hw87-6jcq-9f8q CVE-2026-4053 GO-2026-5442
Mattermost doesn't enforce the PostEditTimeLimit on non-message post fields
- Severity
- 3.1 / 10
- Medium · CVSS 3.1
- Exploit chance (EPSS)
- 0.17%
- Chance of exploitation in the next 30 days. Higher than 5.66% of scored vulnerabilities.
- Known exploited
- No
- Not in CISA's catalog
- Weakness
- CWE-672 Operation on a Resource after Expiration or Release
- Fix
11.5.2- Upgrade github.com/mattermost/mattermost-server to this version or later
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 versions
Go
| Package | Vulnerable | Fixed in |
|---|---|---|
| github.com/mattermost/mattermost-server | >= 11.5.0, < 11.5.2 |
11.5.2 |
| github.com/mattermost/mattermost-server | >= 0.0.0-20250731163400-5b955468ea1e, < 0.0.0-20260414103857-b21ef302025e |
0.0.0-20260414103857-b21ef302025e |
| github.com/mattermost/mattermost-server | >= 0.0.0-20250731163400-5b955468ea1e, < 0.0.0-20260414103857-b21ef302025e>= 11.5.0+incompatible, < 11.5.2+incompatible |
0.0.0-20260414103857-b21ef302025e11.5.2+incompatible |
How to fix
Move to the fixed version or later with your package manager, update the lockfile, and run your tests. If the package only arrives through another dependency, upgrade that dependency first. If none of its releases pulls a fixed version yet, force the version with your package manager's override.
github.com/mattermost/mattermost-server Go → 11.5.2
- go
go get github.com/mattermost/mattermost-server@v11.5.2 && go mod tidy
Severity breakdown
CVSS 3.1 3.1
CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:N/I:L/A:N
- Attack vector
- Network
- Attack complexity
- High
- Privileges required
- Low
- User interaction
- None
- Scope
- Unchanged
- Confidentiality
- None
- Integrity
- Low
- Availability
- None
Weakness
CWE-672: Operation on a Resource after Expiration or Release
The product uses, accesses, or otherwise operates on a resource after that resource has been expired, released, or revoked.
References
Advisories
Packages
Other links
Timeline
- Published
- Last updated by the source
- Latest EPSS score
Related advisories
| Advisory | Severity | Why it's related |
|---|---|---|
| GHSA-xmfh-3ccg-c9fx Mattermost has an Incorrect Authorization issue | Low | Also affects github.com/mattermost/mattermost-server |
| GHSA-h998-hxxj-8q83 Mattermost doesn't invalidate cached authentication state for active WebSocket connections during global session revocation | Medium | Also affects github.com/mattermost/mattermost-server |
| GHSA-g5vr-6pgg-74qv Mattermost doesn't enforce bot-specific permission checks on the user active status endpoint | Low | Also affects github.com/mattermost/mattermost-server |
| GHSA-jqgv-39mg-7c2r Mattermost doesn't authenticate Atlassian Connect installed callbacks, allowing a remote unauthenticated attacker to inject a rogue sharedSecret | Medium | Also affects github.com/mattermost/mattermost-server |
| GHSA-mxq2-5jpg-7474 Mattermost doesn't validate channel ownership of an existing subscription before applying edits | Medium | Also affects github.com/mattermost/mattermost-server |
| GHSA-2g8v-grq3-hq2g Mattermost doesn't enforce administrator authorization on the {{setDefaultInstance}} call within the {{/gitlab connect}} command handler | Medium | Also affects github.com/mattermost/mattermost-server |
| GHSA-6hxm-w4hv-vgvw Mattermost doesn't require role-management authorization when setting the scheme_admin flag on group syncable link and patch endpoints | High | Also affects github.com/mattermost/mattermost-server |
| GHSA-9p44-r552-4wp9 Mattermost doesn't sanitize the Remote Cluster API response on PATCH operations | Medium | Also affects github.com/mattermost/mattermost-server |
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