CVE-2025-6442
Ruby WEBrick read_header HTTP Request Smuggling Vulnerability
- Published
- Updated
- Reserved
- Assigned by
- zdi
Description
Ruby WEBrick read_header HTTP Request Smuggling Vulnerability. This vulnerability allows remote attackers to smuggle arbitrary HTTP requests on affected installations of Ruby WEBrick. This issue is exploitable when the product is deployed behind an HTTP proxy that fulfills specific conditions. The specific flaw exists within the read_headers method. The issue results from the inconsistent parsing of terminators of HTTP headers. An attacker can leverage this vulnerability to smuggle arbitrary HTTP requests. Was ZDI-CAN-21876.
Scores
| Scored by | CVSS | Score | Vector |
|---|---|---|---|
| zdiCNA (assigner) | 3.0 | Medium6.5 | CVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:H/A:N |
| NVDNVD · Analyzed | 3.1 | Medium5.9 | CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:H/A:N |
- EPSS (exploitation in 30 days)
- 0.50% · top 57% of all CVEs (7 Nov 2026)
- CISA SSVC
- Exploitation: none · Automatable: no · Technical impact: partial
The list uses the assigner's score when there is one, then CISA's, then NVD's: Medium 6.5.
Weakness
Affected products
Affected packages
From reviewed advisories of the GitHub Advisory Database.
- RubyGemswebrickGHSA-r995-q44h-hr64 (opens in a new tab)
References (2)
- ZDI-25-414 (opens in a new tab)x_research-advisory
- vendor-provided URL (opens in a new tab)vendor-advisory
Sources
The same CVE in the primary databases and aggregators, to check against.
- CVE.org record (opens in a new tab)
- CVE List JSON (GitHub) (opens in a new tab)
- NVD (opens in a new tab)
- FIRST EPSS (opens in a new tab)
- OSV.dev (opens in a new tab)
- GitHub Advisory GHSA-r995-q44h-hr64 (opens in a new tab)
- CIRCL Vulnerability-Lookup (opens in a new tab)
Badge for a README or a ticket
[](https://trackcve.app/cve/CVE-2025-6442)Record last updated .