Vulnerability Details CVE-2025-6442
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.
Exploit prediction scoring system (EPSS) score
EPSS Score 0.001
EPSS Ranking 15.6%
CVSS Severity
CVSS v3 Score 6.5
References
Products affected by CVE-2025-6442
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cpe:2.3:a:ruby-lang:webrick:-
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cpe:2.3:a:ruby-lang:webrick:1.3.1
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cpe:2.3:a:ruby-lang:webrick:1.4.0
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cpe:2.3:a:ruby-lang:webrick:1.4.1
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cpe:2.3:a:ruby-lang:webrick:1.4.2
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cpe:2.3:a:ruby-lang:webrick:1.4.3
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cpe:2.3:a:ruby-lang:webrick:1.4.4
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cpe:2.3:a:ruby-lang:webrick:1.5.0
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cpe:2.3:a:ruby-lang:webrick:1.5.1
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cpe:2.3:a:ruby-lang:webrick:1.6.0
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cpe:2.3:a:ruby-lang:webrick:1.6.1
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cpe:2.3:a:ruby-lang:webrick:1.7.0
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cpe:2.3:a:ruby-lang:webrick:1.8.0
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cpe:2.3:a:ruby-lang:webrick:1.8.1