Is rack affected by CVE-2026-34786?

RubyGems rack is affected in =3.0.0.beta1 =3.2.0 <3.2.6.

Is CVE-2026-34786 being exploited?

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

medium

CVE-2026-34786

Q: Is CVE-2026-34786 being exploited?

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

RubyGems · rack

Summary

Rack:: Static header_rules bypass via URL-encoded paths

Severity: medium
EPSS: 0.2% (p9)
Also known as: GHSA-q4qf-9j86-f5mh
Published: 2026-04-02

References

https://github.com/rack/rack/security/advisories/GHSA-q4qf-9j86-f5mh
https://nvd.nist.gov/vuln/detail/CVE-2026-34786
https://github.com/rack/rack

Related advisories

CVE-2022-30123 — critical · RubyGems/rack
CVE-2026-34829 — high · RubyGems/rack
CVE-2026-34230 — high · RubyGems/rack
CVE-2026-34827 — high · RubyGems/rack
CVE-2026-34785 — high · RubyGems/rack
CVE-2026-22860 — high · RubyGems/rack
CVE-2025-61919 — high · RubyGems/rack
CVE-2025-61772 — high · RubyGems/rack

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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.