Dompdf up to 3.15 Chroot validateLocalUri chrootPath input validation

Summaryinfo

A vulnerability identified as problematic has been detected in Dompdf up to 3.15. Affected is the function validateLocalUri of the component Chroot. The manipulation of the argument chrootPath leads to input validation. This vulnerability is uniquely identified as CVE-2026-55554. The attack is possible to be carried out remotely. No exploit exists.

Detailsinfo

A vulnerability, which was classified as problematic, has been found in Dompdf up to 3.15. This issue affects the function validateLocalUri of the component Chroot. The manipulation of the argument chrootPath with an unknown input leads to a input validation vulnerability. Using CWE to declare the problem leads to CWE-20. The product receives input or data, but it does not validate or incorrectly validates that the input has the properties that are required to process the data safely and correctly. Impacted is confidentiality. The summary by CVE is:

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.

It is possible to read the advisory at github.com. The identification of this vulnerability is CVE-2026-55554 since 06/17/2026. The exploitation is known to be easy. The attack may be initiated remotely. Technical details of the vulnerability are known, but there is no available exploit.

Upgrading to version 3.16 eliminates this vulnerability.

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Productinfo

Name

• Dompdf

Version

• 3.0
• 3.1
• 3.2
• 3.3
• 3.4
• 3.5
• 3.6
• 3.7
• 3.8
• 3.9
• 3.10
• 3.11
• 3.12
• 3.13
• 3.14
• 3.15

Website

• Product: https://github.com/dompdf/dompdf/

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