CVE-2026-34830

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.

CVSS v3 5.9 MEDIUM

5.9^/10

CVSS v3 : MEDIUM

Vector :

Exploitability : 2.2 / Impact : 3.6

Attack Vector NETWORK

Attack Complexity HIGH

Privileges Required NONE

User Interaction NONE

Confidentiality Impact HIGH

Integrity Impact NONE

Availability Impact NONE

Scope UNCHANGED

References

Link	Resource
https://github.com/rack/rack/security/advisories/GHSA-qv7j-4883-hwh7	Vendor Advisory

Configurations

Configuration 1 (hide)

OR	cpe:2.3:a:rack:rack::::::ruby::*
	cpe:2.3:a:rack:rack::::::ruby::*
	cpe:2.3:a:rack:rack::::::ruby::*

History

16 Apr 2026, 16:50

Type	Values Removed	Values Added
References	~~() https://github.com/rack/rack/security/advisories/GHSA-qv7j-4883-hwh7 -~~	() https://github.com/rack/rack/security/advisories/GHSA-qv7j-4883-hwh7 - Vendor Advisory
CPE		cpe:2.3:a:rack:rack::::::ruby::*
First Time		Rack rack Rack

02 Apr 2026, 17:16

Type	Values Removed	Values Added
New CVE

Information

Published : 2026-04-02 17:16

Updated : 2026-04-16 16:50

NVD link : CVE-2026-34830

Mitre link : CVE-2026-34830

CVE.ORG link : CVE-2026-34830

JSON object : View

Products Affected

rack

rack

CWE

CWE-625

Permissive Regular Expression

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