CVE-2026-26962
Publication date 2 April 2026
Last updated 14 April 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 | 25.10 questing |
Vulnerable
|
| 24.04 LTS noble | Ignored changes too intrusive | |
| 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 changes too intrusive | |
| 14.04 LTS trusty | Ignored changes too intrusive |
Severity score breakdown
| Parameter | Value |
|---|---|
| Base score |
4.8 · Medium
|
| Attack vector | Network |
| Attack complexity | High |
| Privileges required | None |
| User interaction | None |
| Scope | Unchanged |
| Confidentiality | Low |
| Integrity impact | Low |
| Availability impact | None |
| Vector | CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:N |