---
id: CVE-2026-120634
title: >-
  CGI::Carp versions before 5.00 for Perl leak warnings across requests in
  persistent environments via the warningsToBrowser buffer
summary: >-
  CGI::Carp versions before 5.00 for Perl leak warnings across requests in
  persistent environments via the warningsToBrowser buffer.


  Warnings are held in a package-level buffer until warningsToBrowser writes
  them into the page as HTML com…
severity: none
cwe:
  - CWE-488
product: CGI
affected:
  - CGI < 5.00
published: '2026-11-03'
updated: '2026-11-03'
sourceUpdated: '2026-11-03T23:40:08.097Z'
source: CVEORG
sourceUrl: 'https://www.cve.org/CVERecord?id=CVE-2026-120634'
references:
  - url: 'https://metacpan.org/release/LEEJO/CGI-4.72/source/lib/CGI/Carp.pm'
  - url: 'https://metacpan.org/release/LEEJO/CGI-5.00/changes'
  - url: >-
      https://github.com/leejo/CGI.pm/commit/604a83fec105f75fe06f1a75026c4c34fd5a1f61.patch
tags:
  - cve.org
epss: 0.00191
epssPercentile: 0.08842
ingestedAt: '2026-11-05T20:33:06.614Z'
---

## Overview

CGI::Carp versions before 5.00 for Perl leak warnings across requests in persistent environments via the warningsToBrowser buffer.

Warnings are held in a package-level buffer until warningsToBrowser writes them into the page as HTML comments, and the buffer is never cleared between requests. Under mod_perl, FastCGI or PSGI, warnings from one request are written into a later one.

Warnings that contain one user's request data can appear in the HTML sent to another user.

## Affected

- `CGI < 5.00`

## Remediation

Upgrade to CGI 5.00 or later.

### Workarounds

For deployments that cannot upgrade, do not use warningsToBrowser in persistent environments. After upgrading, persistent applications where nothing calls CGI::initialize_globals between requests must also call CGI::Carp::_reset_globals at the start of each request.