Quick answers
- Is CVE-2026-120631 exploited in the wild?
- No. Junglewise Threat Intelligence has no report of CVE-2026-120631 being exploited in the wild.
- How severe is CVE-2026-120631?
- Informational severity, published 4 November 2026.
- Which products and versions are affected?
- Perl CGI::Cookie 4.67 to before 5.00.
- Is there a fix for CVE-2026-120631?
- Yes: fixed in CGI::Cookie 5.00 and later. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.
- How is CVE-2026-120631 attacked?
- It is attacked over the network, in a software library.
- Am I affected by CVE-2026-120631?
- Check whether you run Perl CGI::Cookie at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.
How to fix
- Fixed in: CGI::Cookie 5.00 and later
Technical details
CGI::Cookie::parse() interpolates the client-supplied "expires" cookie value unescaped into a regex substitution pattern, enabling regex injection. An attacker can supply specially crafted expires values—such as invalid regex syntax like '(' or pathological patterns like '(a|aa|aaa)*\1b'—to cause the process to die with a regex error or hang indefinitely from backtracking. The fix replaces the pattern-based removal with position-based string manipulation via substr().
Affected products
- Perl CGI::Cookie 4.67 to before 5.00
Timeline
- 2026-11-04: disclosed
- 2026-11-02: patched: Fix commit authored 2026-11-02