EUVD-2026-18417
GHSA-rx22-g9mx-qrhv
CVSS Vector
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:N
Lifecycle Timeline
4Tags
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.
Analysis
Rack versions 3.2.0 through 3.2.5 fail to properly unfold folded multipart headers containing obs-fold sequences, preserving embedded CRLF characters in parsed parameter values like filename and name. This allows unauthenticated remote attackers with high request complexity to inject HTTP response headers or split responses when applications reuse these parsed values, leading to potential session hijacking, cache poisoning, or credential theft. …
Sign in for full analysis, threat intelligence, and remediation guidance.
Priority Score
Vendor Status
Share
External POC / Exploit Code
Leaving vuln.today