CVE-2021-41816: Fedoraproject Fedora

Critical severity, CVSS 9.8. EPSS: 4.9% chance of exploitation in the next 30 days.

CGI.escape_html in Ruby before 2.7.5 and 3.x before 3.0.3 has an integer overflow and resultant buffer overflow via a long string on platforms (such as Windows) where size_t and long have different numbers of bytes. This also affects the CGI gem before 0.3.1 for Ruby.

Affected products

• Fedoraproject Fedora: version 34 only; version 35 only
• Ruby-Lang Cgi: before 0.3.1 (fixed in 0.3.1); up to and including 0.2.0; up to and including 0.1.0

Published 2022-02-06. Last modified 2026-06-17.