CVE-2025-6442

NameCVE-2025-6442
DescriptionRuby 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.
SourceCVE (at NVD; CERT, LWN, oss-sec, fulldisc, Red Hat, Ubuntu, Gentoo, SUSE bugzilla/CVE, GitHub advisories/code/issues, web search, more)

Vulnerable and fixed packages

The table below lists information on source packages.

Source PackageReleaseVersionStatus
ruby-webrick (PTS)bookworm1.8.1-1vulnerable
sid, trixie1.9.1-1fixed

The information below is based on the following data on fixed versions.

PackageTypeReleaseFixed VersionUrgencyOriginDebian Bugs
ruby-webricksource(unstable)1.9.1-1

Notes

https://www.zerodayinitiative.com/advisories/ZDI-25-414/
Fixed by: https://github.com/ruby/webrick/commit/ee60354bcb84ec33b9245e1d1aa6e1f7e8132101 (v1.8.2)

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