CVE-2026-34830

5.9 MEDIUM
Published: April 02, 2026 Modified: April 16, 2026
View on NVD

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.

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CVSS v3.x Details

0.0 Low Medium High Critical 10.0
Vector String
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N

References to Advisories, Solutions, and Tools

Patch Vendor Advisory Exploit Third Party Advisory
https://github.com/rack/rack/security/advisories/GHSA-qv7j-4883-hwh7
Source: security-advisories@github.com
Vendor Advisory

1 reference(s) from NVD

Quick Stats

CVSS v3 Score
5.9 / 10.0
EPSS (Exploit Probability)
0.0%
13th percentile
Exploitation Status
Not in CISA KEV

Weaknesses (CWE)

Affected Vendors

rack