Is github.com/mattermost/mattermost-server affected by CVE-2026-4054?

Go github.com/mattermost/mattermost-server is affected in >=11.5.0 =0.0.0-20250731163400-5b955468ea1e =11.4.0 <11.4.4.

Is CVE-2026-4054 being exploited?

Not on the CISA KEV list. EPSS exploit probability is 0.2%.

medium

CVE-2026-4054

Q: Is CVE-2026-4054 being exploited?

Not on the CISA KEV list. EPSS exploit probability is 0.2%.

Go · github.com/mattermost/mattermost-server

Summary

Mattermost doesn't validate the response body of proxied images

Severity: medium
EPSS: 0.2% (p15)
Also known as: GHSA-j76w-p754-g2w7
Published: 2026-05-15

References

Related advisories

CVE-2026-6346 — high · Go/github.com/mattermost/mattermost-server
CVE-2026-6347 — high · Go/github.com/mattermost/mattermost-server
CVE-2026-6339 — medium · Go/github.com/mattermost/mattermost-server
CVE-2026-5163 — medium · Go/github.com/mattermost/mattermost-server
CVE-2026-28732 — medium · Go/github.com/mattermost/mattermost-server
CVE-2026-6345 — medium · Go/github.com/mattermost/mattermost-server
CVE-2026-6340 — medium · Go/github.com/mattermost/mattermost-server
CVE-2026-3637 — medium · Go/github.com/mattermost/mattermost-server

Is your project exposed to this? Stateward checks every dependency on every pull request and flags it only if your code actually reaches it.

Check my repo

Summarize with AI

ChatGPT Claude Perplexity

Sources: CISA KEV (public domain), OSV.dev & GitHub Advisory Database (CC-BY-4.0), FIRST EPSS, NVD/CWE (public domain). Served live from the Stateward advisory database.