Bug 2566596 (CVE-2026-120643)

Summary: CVE-2026-120643 perl-CGI: perl-CGI: Cross-site scripting via unescaped apostrophes in generated URLs
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-CGI. When constructing Uniform Resource Locators (URLs), the url() and self_url() functions fail to properly encode single quote characters in request paths or query parameters. A remote attacker can exploit this issue by submitting a crafted request to an application that embeds these URLs into single-quoted web page attributes or script blocks. This can result in cross-site scripting (XSS), allowing an attacker to execute malicious scripts in an affected user's browser and potentially access sensitive session data.
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Description OSIDB Bzimport 2026-11-03 23:51:37 UTC 
CGI versions from 4.62 before 5.00 for Perl allow cross-site scripting via a raw apostrophe in URLs returned by url and self_url.

Both pass the URL through URI's canonical method, which leaves an apostrophe in the path raw and decodes the %27 that query parameter escaping produces, so an apostrophe in the request path or a parameter appears raw in the result.

An application that places the URL in a single-quoted HTML attribute or JavaScript string is open to cross-site scripting.