SecuriTricks - CVE-2026-34830

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.

Product(s) Impacted

Vendor	Product	Versions
Ruby	Rack	<2.2.23, <3.1.21, <3.2.6

Weaknesses

Common security weaknesses mapped to this vulnerability.

CWE-625

Permissive Regular Expression

The product uses a regular expression that does not sufficiently restrict the set of allowed values.

*CPE(s)

Affected systems and software identified for this CVE.

Type	Vendor	Product	Version	Update	Edition	Language	Software Edition	Target Software	Target Hardware	Other Information
a	ruby	rack	<2.2.23	/	/	/	/	/	/	/
a	ruby	rack	<3.1.21	/	/	/	/	/	/	/
a	ruby	rack	<3.2.6	/	/	/	/	/	/	/

References

https://github.com/rack/rack/security/advisories/GHSA-qv7j-4883-hwh7

CVSS Score

5.9 / 10

CVSS Data - 3.1

Attack Vector: NETWORK
Attack Complexity: HIGH
Privileges Required: NONE
Scope: UNCHANGED
Confidentiality Impact: HIGH
Integrity Impact: NONE
Availability Impact: NONE

CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N

View Vector String

Timeline

Published: April 2, 2026, 5:16 p.m.
Last Modified: April 3, 2026, 4:10 p.m.

Status : Undergoing Analysis

CVE has been recently published to the CVE List and has been received by the NVD.

More info

Source

[email protected]

CVE-2026-34830