Quick answers
- Is CVE-2026-120632 exploited in the wild?
- No. Junglewise Threat Intelligence has no report of CVE-2026-120632 being exploited in the wild.
- How severe is CVE-2026-120632?
- Informational severity, published 4 November 2026.
- Which products and versions are affected?
- Perl CGI before 5.00.
- Is there a fix for CVE-2026-120632?
- Yes: fixed in CGI 5.00. Until then: The fix refactors the pattern into separate linear-time matches for boundary= and start= parameters instead of a single pattern with backtracking, and requires the Content-Type to begin with multipart/related rather than contain it anywhere. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.
- How is CVE-2026-120632 attacked?
- It is attacked over the network, in a software library.
- Am I affected by CVE-2026-120632?
- Check whether you run Perl CGI 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 5.00
The fix refactors the pattern into separate linear-time matches for boundary= and start= parameters instead of a single pattern with backtracking, and requires the Content-Type to begin with multipart/related rather than contain it anywhere.
Technical details
The vulnerability is a regular expression denial of service (ReDoS) in the parsing of XForms multipart/related Content-Type headers. The regex pattern used .+ on either side of a repeated group, causing cubic-time backtracking O(n³) when a crafted header (such as repeated "boundary=a " with no matching "start=" parameter) fails to match. An unauthenticated remote attacker can trigger this via a POST request header with no body required.
Affected products
- Perl CGI before 5.00
Timeline
- 2026-11-04: disclosed
- 2026-11-02: patched