CVE-2026-26962
As a result, applications that later reuse those parsed values in HTTP response headers may be vulnerable to downstream header injection or response splitting.
Does this matter?
Lower severity and a low EPSS score (0.23%). Track it; it rarely justifies an emergency change on its own.
Description
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 embedded CRLF in parsed parameter values such as filename or name instead of removing the folded line break during unfolding. As a result, applications that later reuse those parsed values in HTTP response headers may be vulnerable to downstream header injection or response splitting. This issue has been patched in version 3.2.6.
- CVSS 3.1
- 6.5 MEDIUMCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N
- EPSS
- 0.23% probability · 13th percentile
- Public exploits
- None in Exploit-DB
- CISA KEV
- Not listed
- Weakness
- CWE-93
- Affected
- rack/rack
- Source
- security-advisories@github.com
EPSS 0.2% since 27 October 2026; no change recorded yet. Points are recorded when the score first appears and whenever it moves by a percentage point or more.
References
- https://github.com/rack/rack/security/advisories/GHSA-rx22-g9mx-qrhvMitigation, Vendor Advisory
Source: NVD record, EPSS from FIRST.org, KEV from CISA, exploits from Exploit-DB. Refreshed daily. Download this record as JSON.