CVE-2026-120634

CGI::Carp versions before 5.00 for Perl leak warnings across requests in persistent environments via the warningsToBrowser buffer.

Warnings are held in a package-level buffer until warningsToBrowser writes them into the page as HTML comments, and the buffer is never cleared between requests. Under mod perl, FastCGI or PSGI, warnings from one request are written into a later one.

Warnings that contain one user's request data can appear in the HTML sent to another user.