What is CVE-2026-26962?

CVE-2026-26962 is a medium-severity vulnerability in Rack, classified under CRLF Injection. CVSS score: 4.8/10. Published 2026-04-02.

How severe is CVE-2026-26962?

Medium severity. CVSS v3 base score is 4.8 out of 10.

Vulnerability in Rack

CVE-2026-26962

Rack is a modular Ruby web server interface. From version 3.2.0 to before version 3.2.6, Rack::Multipart::Parser unfolds folded multipart part headers incorrectly. When a multipart header contains an obs-fold sequence, Rack preserves the e…

Vulnerability class: CRLF Injection

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

CVSS v3 metric

CVSS v3 base score 4.8 (Medium). Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:N.

Affected products

Rack — versions >= 3.2.0, < 3.2.6

Weakness classification (CWE)

CWE-93 — CRLF Injection

References

https://github.com/rack/rack/security/advisories/GHSA-rx22-g9mx-qrhv (x_refsource_CONFIRM)

Frequently asked questions

What is CVE-2026-26962?: CVE-2026-26962 is a medium-severity vulnerability in Rack, classified under CRLF Injection. CVSS score: 4.8/10. Published 2026-04-02.
How severe is CVE-2026-26962?: Medium severity. CVSS v3 base score is 4.8 out of 10.