Bug 2566593 (CVE-2026-120632)

Summary: CVE-2026-120632 perl-CGI: perl-CGI: Denial of Service via crafted multipart/related Content-Type header
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security DevOps Team <prodsec-dev>
Status: NEW --- QA Contact:
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Priority: medium    
Version: unspecifiedCC: rhel-process-autobot, watson-tool-maintainers
Target Milestone: ---Keywords: Security
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Hardware: All   
OS: Linux   
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A flaw was found in the Perl CGI module. This vulnerability allows a remote attacker to cause a Denial of Service (DoS) by sending a specially crafted HTTP request. Due to an inefficient regular expression used when parsing multipart/related Content-Type headers, processing non-matching headers triggers catastrophic backtracking. This results in excessive CPU resource exhaustion and renders the application unresponsive, even without a request body.
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oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
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Bug Depends On: 2567305    
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Description OSIDB Bzimport 2026-11-03 23:51:24 UTC
CGI versions before 5.00 for Perl allow CPU exhaustion via a backtracking regex on the XForms multipart/related Content-Type.

When a POST Content-Type contains multipart/related, the boundary and start parameters are extracted with an unanchored pattern that puts .+ on either side of the boundary capture, which backtracks in cubic time on a header that does not match. No request body is needed.