CVE-2026-34835 - Vulnerability Analysis
MediumCVSS: 4.8Last Updated: April 3, 2026
Rack - Host Header Injection
Published: April 2, 2026Updated: April 3, 2026PoC AvailableRemote Exploitable
Overview
Rack 3.0.0.beta1 to < 3.1.21 and 3.2.0 to < 3.2.6 contain a host header poisoning vulnerability caused by improper parsing of the Host header in Rack::Request, letting attackers bypass host validation and poison links or redirects, exploit requires crafted Host header.
Severity & Score
Severity: Medium
CVSS Score: 4.8
Impact
Attackers can poison host headers to bypass validation, causing malicious redirects or link generation issues.
Mitigation
Update to versions 3.1.21 or 3.2.6 or later.
Related Resources
Details
- CVE ID
- CVE-2026-34835
- Severity
- Medium
- CVSS Score
- 4.8
- Type
- host_header_injection
- Status
- confirmed
CWE
- CWE-1286
CVSS Metrics
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:N