CVEvulnerability

CVE-2026-34835

6.5 MEDIUM Published 2026-04-02 Modified 2026-07-24 Official page ↗
Status
Analyzed
Published
2026-04-02
Last modified
2026-07-24
Assigner
[email protected]
CVSS 3.1 ([email protected])
4.8 MEDIUM — CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:N
CVSS 3.1 ([email protected])
6.5 MEDIUM — CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N
Weaknesses
CWE-1286

Description

Rack is a modular Ruby web server interface. From versions 3.0.0.beta1 to before 3.1.21, and 3.2.0 to before 3.2.6, Rack::Request parses the Host header using an AUTHORITY regular expression that accepts characters not permitted in RFC-compliant hostnames, including /, ?, #, and @. Because req.host returns the full parsed value, applications that validate hosts using naive prefix or suffix checks can be bypassed. This can lead to host header poisoning in applications that use req.host, req.url, or req.base_url for link generation, redirects, or origin validation. This issue has been patched in versions 3.1.21 and 3.2.6.

Affected configurations

• rack rack (>= 3.0.0 < 3.1.21) • rack rack (>= 3.2.0 < 3.2.6)

Related

Weakness · CWE (1)

  • CWE-1286 Improper Validation of Syntactic Correctness of Input weakness

References