---
id: CVE-2026-120632
title: >-
  CGI versions before 5.00 for Perl allow CPU exhaustion via a backtracking
  regex on the XForms multipart/related Content-Type
summary: >-
  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 u…
severity: none
cwe:
  - CWE-1333
product: CGI
affected:
  - CGI < 5.00
published: '2026-11-03'
updated: '2026-11-03'
sourceUpdated: '2026-11-03T23:40:01.071Z'
source: CVEORG
sourceUrl: 'https://www.cve.org/CVERecord?id=CVE-2026-120632'
references:
  - url: 'https://metacpan.org/release/LEEJO/CGI-4.72/source/lib/CGI.pm'
  - url: 'https://metacpan.org/release/LEEJO/CGI-5.00/changes'
  - url: >-
      https://github.com/leejo/CGI.pm/commit/1e529c7ac8d410a51b4b04ab9d6cc00d51ef33c0.patch
tags:
  - cve.org
epss: 0.00191
epssPercentile: 0.08841
ingestedAt: '2026-11-05T20:33:06.613Z'
---

## Overview

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.

## Affected

- `CGI < 5.00`

## Remediation

Upgrade to CGI 5.00 or later.

### Workarounds

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