---
id: "CVE-2026-120645"
kind: "vulnerability"
aliases: ["CVE-2026-120645"]
title: "Perl CGI: crafted form values can crash or stall scrolling_list rendering"
severity: "unknown"
cvss: null
epss: null
exploited: false
status: "open"
category: "package"
products: []
ecosystems: []
tags: ["cgi", "package", "perl", "self-hosted"]
not_affected_if: ["no-scrolling-list", "static-values"]
published_at: "2026-11-04T00:17:26+00:00"
first_seen_at: "2026-11-04T00:46:17+00:00"
updated_at: "2026-11-04T00:48:10+00:00"
sources: [{"source": "nvd", "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-120645", "first_seen_at": "2026-11-04T00:46:17+00:00"}]
---

# Perl CGI: crafted form values can crash or stall scrolling_list rendering

The Perl CGI module before 5.00 interpolates submitted request values unescaped into a regular expression when rendering option groups in scrolling_list. A remote client can send a value that makes the request die on an invalid pattern or consume the process with heavy backtracking, causing denial of service.

_Summary, check and fix written by a model from the sources; labelled as such._

## How to check

- Check the installed CGI module version with `perl -MCGI -e 'print $CGI::VERSION'`
- Search application code for calls to `scrolling_list` that pass request parameters as selected values

## Fix

- Upgrade CGI to `5.00` or later

## Timeline

- 2026-11-04T00:46:17+00:00 nvd https://nvd.nist.gov/vuln/detail/CVE-2026-120645

## Documents

- [fix] Patch: github.com https://github.com/leejo/CGI.pm/commit/824956fbb0c4eb77044ba2dc9180a30df12cb309.patch

## From the sources

CGI versions before 5.00 for Perl allow denial of service via submitted values used as a regex for optgroup selection in scrolling_list.

When rendering option groups, scrolling_list marks the selected options by interpolating each selected value, by default taken from the request parameters, unescaped into a substitution pattern.

A client can make the request die with an invalid pattern, or tie up the process with one that backtracks heavily.

---

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