CVE-2026-26962
Publication date 2 April 2026
Last updated 3 November 2026
Ubuntu priority
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.
Status
| Package | Ubuntu Release | Status |
|---|---|---|
| ruby-rack | 26.10 stonking |
Not affected
|
| 26.04 LTS resolute |
Fixed in 3.2.4-1ubuntu1.1
|
|
| 24.04 LTS noble |
Fixed in 2.2.7-1ubuntu0.7
|
|
| 22.04 LTS jammy | Ignored changes too intrusive | |
| 20.04 LTS focal | Ignored changes too intrusive | |
| 18.04 LTS bionic | Ignored changes too intrusive | |
| 16.04 LTS xenial | Ignored end of ESM support, was ignored [changes too intrusive] | |
| 14.04 LTS trusty | Ignored changes too intrusive |
Severity score breakdown
CVSS version: CVSS v3.0
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
References
Related Ubuntu Security Notices (USN)
- USN-8182-1
- Rack vulnerabilities
- 17 April 2026
- USN-8989-1
- Rack vulnerabilities
- 3 November 2026