Vulnerability · Published Jul 28, 2026 · Assigned by GitHub_M
CVE-2026-55554Dompdf: Chroot Validation Bypass
Low 2.3
In plain English
A low-severity improper input validation in dompdf from dompdf. Proof-of-concept exploit code is public. The chance it is exploited in the next 30 days is estimated at 0.5% (higher than 39% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.
Official 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.
Affected packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| Debian:12 | php-dompdf | no fix listed | DEBIAN-CVE-2026-55554 |
| Packagist | dompdf/dompdf | 3.1.6 | GHSA-wvh6-f5jh-8gw4 |
| Ubuntu:22.04:LTS | php-dompdf | no fix listed | UBUNTU-CVE-2026-55554 |
Affected products (as reported)
Weakness: CWE-20 · 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
References
- https://github.com/dompdf/dompdf/security/advisories/GHSA-wvh6-f5jh-8gw4 x_refsource_CONFIRM
- https://github.com/dompdf/dompdf/releases/tag/v3.1.6 x_refsource_MISC