CGI versions before 5.00 for Perl allow CPU exhaustion via a backtracking regex on the XForms multipart/related Content-Type.

When a POST Content-Type contains multipart/related, the boundary and start parameters are extracted with an unanchored pattern that puts .+ on either side of the boundary capture, which backtracks in cubic time on a header that does not match. No request body is needed.

Project Subscriptions

No data.

Advisories

No advisories yet.

Fixes

Solution

Upgrade to CGI 5.00 or later.


Workaround

For deployments that cannot upgrade, reject Content-Type request headers longer than 1KB at the web server.

History

Wed, 04 Nov 2026 00:00:00 +0000

Type Values Removed Values Added
Description CGI versions before 5.00 for Perl allow CPU exhaustion via a backtracking regex on the XForms multipart/related Content-Type. When a POST Content-Type contains multipart/related, the boundary and start parameters are extracted with an unanchored pattern that puts .+ on either side of the boundary capture, which backtracks in cubic time on a header that does not match. No request body is needed.
Title CGI versions before 5.00 for Perl allow CPU exhaustion via a backtracking regex on the XForms multipart/related Content-Type
Weaknesses CWE-1333
References

Projects

Sign in to view the affected projects.

cve-icon MITRE

Status: PUBLISHED

Assigner: CPANSec

Published:

Updated: 2026-11-03T23:40:01.071Z

Reserved: 2026-11-02T17:39:55.528Z

Link: CVE-2026-120632

cve-icon Vulnrichment

No data.

cve-icon NVD

Status : Received

Published: 2026-11-04T00:17:24.320

Modified: 2026-11-04T00:17:24.320

Link: CVE-2026-120632

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

No data.

Weaknesses