CVE-2026-4054

medium

Published 2026-05-15 · Modified 2026-05-28

💬 Discuss on Community ✚ Propose mitigation

CVSS v3

6.5

CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:L

CVSS v4 NEW

—

not yet in upstream

VIR risk

6.5

Description

Mattermost doesn't validate the response body of proxied images

Predictions

Exploit likelihood

75%

Patch ETA

—

Heuristic predictions, AS-IS, for prioritization only.

Mitigations

No mitigations published for this CVE yet.

The vendor-content worker queues fetches as references arrive (check back in a few minutes). Or — if you've already worked around this in production — publish your fix to the community-verified tier.

✚ Propose a mitigation on Community → Mitigations published via the community go through AI scoring + 2 human reviewers + 7-day silent objection window before landing here with source_tier=community-verified.

Package impact

Ecosystem	Package	Vulnerable	Fixed
Go	github.com/mattermost/mattermost-server	`>=11.5.0,<11.5.2`	`11.5.2`
Go	github.com/mattermost/mattermost-server	`>=0.0.0-20250731163400-5b955468ea1e,<0.0.0-20260414103857-b21ef302025e`	`0.0.0-20260414103857-b21ef302025e`
Go	github.com/mattermost/mattermost-server	`>=11.4.0,<11.4.4`	`11.4.4`

Application impact

Vendor	Product	Versions	Fixed
mattermost	mattermost_server	`{"startIncluding":"10.11.0","endExcluding":"10.11.14"}`	`10.11.14`

References

CWEs

CWE-754

Community-verified mitigations for this CVE will appear above when contributors publish them.

Verify integrity in audit chain (admin only). AS-IS.