CVE-2026-34830
Publication date 2 April 2026
Last updated 23 April 2026
Ubuntu priority
Description
Rack is a modular Ruby web server interface. Prior to versions 2.2.23, 3.1.21, and 3.2.6, Rack::Sendfile#map_accel_path interpolates the value of the X-Accel-Mapping request header directly into a regular expression when rewriting file paths for X-Accel-Redirect. Because the header value is not escaped, an attacker who can supply X-Accel-Mapping to the backend can inject regex metacharacters and control the generated X-Accel-Redirect response header. In deployments using Rack::Sendfile with x-accel-redirect, this can allow an attacker to cause nginx to serve unintended files from configured internal locations. This issue has been patched in versions 2.2.23, 3.1.21, and 3.2.6.
Status
| Package | Ubuntu Release | Status |
|---|---|---|
| ruby-rack | 25.10 questing |
Fixed 3.1.16-0.1ubuntu0.3
|
| 24.04 LTS noble |
Fixed 2.2.7-1ubuntu0.7
|
|
| 22.04 LTS jammy |
Fixed 2.1.4-5ubuntu1.2+esm3
|
|
| 20.04 LTS focal |
Fixed 2.0.7-2ubuntu0.1+esm10
|
|
| 18.04 LTS bionic |
Fixed 1.6.4-4ubuntu0.2+esm10
|
|
| 16.04 LTS xenial |
Fixed 1.6.4-3ubuntu0.2+esm10
|
|
| 14.04 LTS trusty | Ignored changes too intrusive |
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| Parameter | Value |
|---|---|
| Base score |
5.9 · Medium
|
| Attack vector | Network |
| Attack complexity | High |
| Privileges required | None |
| User interaction | None |
| Scope | Unchanged |
| Confidentiality | High |
| Integrity impact | None |
| Availability impact | None |
| Vector | CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N |
References
Related Ubuntu Security Notices (USN)
- USN-8182-1
- Rack vulnerabilities
- 17 April 2026