Is github.com/mattermost/mattermost/server/v8 affected by CVE-2026-3590?

Go github.com/mattermost/mattermost/server/v8 is affected in >=8.0.0-20250721062209-4952acea88ce <8.0.0-20250723052842-4cb8d8940332.

Is CVE-2026-3590 being exploited?

Not on the CISA KEV list. EPSS exploit probability is 0.1%.

medium

CVE-2026-3590

Q: Is CVE-2026-3590 being exploited?

Not on the CISA KEV list. EPSS exploit probability is 0.1%.

Go · github.com/mattermost/mattermost/server/v8 • Go · github.com/mattermost/mattermost-server

Summary

Mattermost has session spoofing due to lack of single-use consumption of guest magic link tokens enforcement

Severity: medium
EPSS: 0.1% (p4)
Also known as: GHSA-mh4x-rmrx-3hp4#github.com/mattermost/mattermost-server, GHSA-mh4x-rmrx-3hp4#github.com/mattermost/mattermost/server/v8
Published: 2026-04-17

References

Related advisories

CVE-2026-6346 — high · Go/github.com/mattermost/mattermost/server/v8
CVE-2026-3108 — high · Go/github.com/mattermost/mattermost/server/v8
CVE-2026-6339 — medium · Go/github.com/mattermost/mattermost/server/v8
CVE-2026-6343 — medium · Go/github.com/mattermost/mattermost/server/v8
CVE-2026-5163 — medium · Go/github.com/mattermost/mattermost/server/v8
CVE-2026-28732 — medium · Go/github.com/mattermost/mattermost/server/v8
CVE-2026-6345 — medium · Go/github.com/mattermost/mattermost/server/v8
CVE-2026-6340 — medium · Go/github.com/mattermost/mattermost/server/v8

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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.