CVE-2026-55554 Dompdf: Chroot Validation Bypass
An attacker can bypass chroot restrictions in Dompdf to read sensitive files outside the allowed directory by exploiting a flawed path validation check.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- A user has to click or open something
- Fix
- Available
What is CVE-2026-55554?
CVE-2026-55554 is a low-severity path traversal vulnerability in dompdf, published on 28 Jul 2026. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.
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.
Weakness: CWE-20
Which versions are affected by CVE-2026-55554?
2 open source packages ship an affected version, including dompdf/dompdf. It affects 1 product.
| Package | Affected | Fixed in |
|---|---|---|
dompdf/dompdf Packagist | All versions | 3.1.6 |
dompdf/dompdf Packagist | All versions | 3.1.6 |
Products include Dompdf Project Dompdf.
How do I fix CVE-2026-55554?
Upgrade dompdf/dompdf to 3.1.6 or later.
Upgrade, and resolve every user-supplied path against an allowed base folder before opening it. More about Path traversal.
Is CVE-2026-55554 being exploited?
It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-55554 exists.
Other vulnerabilities in dompdf
- CVE-2023-24813 URI validation failure on SVG parsing. Bypass of CVE-2023-23924
- CVE-2023-23924 URI validation failure on SVG parsing in Dompdf
- CVE-2021-3838 PHAR Deserialization in dompdf/dompdf
- CVE-2021-3902 Improper Restriction of XML External Entity Reference in dompdf/dompdf
- CVE-2022-28368 Remote code injection in dompdf/dompdf
Sources
Also known as DEBIAN-CVE-2026-55554, GHSA-wvh6-f5jh-8gw4, UBUNTU-CVE-2026-55554.