Bug 2563045 (CVE-2026-116268)

Summary: CVE-2026-116268 perl-MIME-tools: perl-MIME-tools: Denial of Service via unclosed comments in header parameters
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security DevOps Team <prodsec-dev>
Status: NEW --- QA Contact:
Severity: medium Docs Contact:
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 perl-MIME-tools. A remote attacker can cause a Denial of Service (DoS) by supplying specially crafted Multipurpose Internet Mail Extensions (MIME) headers containing unclosed comments. Due to inefficient parsing of parameters lacking closing parentheses, the parser repeatedly scans the remainder of the header, leading to excessive CPU consumption and application unresponsiveness.
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oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
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Bug Depends On: 2563414, 2563427    
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Description OSIDB Bzimport 2026-10-28 17:41:54 UTC
MIME::Field::ParamVal versions before 5.521 for Perl allow CPU exhaustion via unclosed comments in header parameters.

The comment pattern used to parse Content-Type and Content-Disposition parameters scans from each "(" to the next ")". In a field with no ")", every "(" scans to the end of the header and fails, so parsing takes time quadratic in the header length. The field is parsed again on each attribute lookup, several times per MIME entity.

A 40 KB header takes about 7 seconds to parse once.