What is CVE-2026-34827?

CVE-2026-34827 is a high-severity vulnerability in Rack, classified under Inefficient Algorithmic Complexity. CVSS score: 7.5/10. Published 2026-04-02.

How severe is CVE-2026-34827?

High severity. CVSS v3 base score is 7.5 out of 10.

Resource exhaustion in Rack

CVE-2026-34827

Rack is a modular Ruby web server interface. From versions 3.0.0.beta1 to before 3.1.21, and 3.2.0 to before 3.2.6, Rack::Multipart::Parser#handle_mime_head parses quoted multipart parameters such as Content-Disposition: form-data; name="…

EPSS: 0.000 (6.4th percentile) — read the EPSS interpretation.

CVSS v3 metric

CVSS v3 base score 7.5 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H.

Affected products

Rack — versions >= 3.0.0.beta1, < 3.1.21, >= 3.2.0, < 3.2.6

Weakness classification (CWE)

CWE-407 — Inefficient Algorithmic Complexity
CWE-400 — Uncontrolled Resource Consumption
CWE-770 — Allocation of Resources Without Limits or Throttling

References

https://github.com/rack/rack/security/advisories/GHSA-v6x5-cg8r-vv6x (x_refsource_CONFIRM)

Frequently asked questions

What is CVE-2026-34827?: CVE-2026-34827 is a high-severity vulnerability in Rack, classified under Inefficient Algorithmic Complexity. CVSS score: 7.5/10. Published 2026-04-02.
How severe is CVE-2026-34827?: High severity. CVSS v3 base score is 7.5 out of 10.