Is github.com/mattermost/mattermost-server affected by CVE-2026-26233?

Go github.com/mattermost/mattermost-server is affected in >=10.11.0-rc1+incompatible =11.2.0-rc1+incompatible =11.3.0-rc1+incompatible =11.4.0-rc1+incompatible <11.4.1+incompatible.

Is CVE-2026-26233 being exploited?

Not on the CISA KEV list. EPSS exploit probability is 0.3%.

medium

CVE-2026-26233

Q: Is CVE-2026-26233 being exploited?

Not on the CISA KEV list. EPSS exploit probability is 0.3%.

Go · github.com/mattermost/mattermost-server

Summary

Mattermost doesn't rate limit login requests, allowing DoS in github.com/mattermost/mattermost-server

Severity: medium
EPSS: 0.3% (p22)
Also known as: GHSA-247x-7qw8-fp98, GO-2026-4916
Published: 2026-04-02

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

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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.