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TI-2026-40098 Aliases CVE-2026-55554GHSA-wvh6-f5jh-8gw4

Dompdf: Chroot Validation Bypass

Priority MEDIUM 45CWE-20Published · Updated

Key facts

Attack vector
Network
Privileges required
None
User interaction
Passive
Attack complexity
Low
Attack requirements
Present
Impact type
Information disclosure
Confidentiality · integrity · availability
Low · None · None
Fix status
Fixed

Attack profile from CVSS 4.0 · CNA. Fix status from CNA and GitHub. Impact type from CWE-22 and the CVSS impact.

Summary

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.

Why it matters now

Exploitation Proof of concept CISA SSVC · not in CISA KEV
EPSS 0.00451 39th percentileScored 2026-11-07
Public exploit Yes 1 exploit referenceTagged by NVD
Fix Fixed dompdf (dompdf): 3.1.6dompdf/dompdf (Packagist): 3.1.6

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation
Poc
Automatable
No
Technical impact
Partial

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

VendorProductAffected versionsFixed inStatusSource
dompdfdompdfbefore 3.1.63.1.6Patch availableCNA
—dompdf/dompdf (Packagist)before 3.1.63.1.6Patch availableGHSA-wvh6-f5jh-8gw4
  • dompdf Vendordompdf Affected before 3.1.6 Fixed in 3.1.6 Patch available CNA
  • dompdf/dompdf (Packagist) Vendor— Affected before 3.1.6 Fixed in 3.1.6 Patch available GHSA-wvh6-f5jh-8gw4

CPE configurations NVD · 1

CPEVersionsRoleVendor
cpe:2.3:a:dompdf_project:dompdf:*:*:*:*:*:*:*:*before 3.1.6VulnerableDompdf Project
  • cpe:2.3:a:dompdf_project:dompdf:*:*:*:*:*:*:*:* Versions before 3.1.6 Vulnerable ·Dompdf Project

Remediation

  • Fix · CNA dompdf (dompdf) Fixed in 3.1.6
  • Fix · GHSA-wvh6-f5jh-8gw4 dompdf/dompdf (Packagist) Fixed in 3.1.6 Advisory →

Timeline

  1. 2026-10-02 Threatist record created from CVE-2026-55554
  2. 2026-10-03 Alias added: GHSA-wvh6-f5jh-8gw4

References

Exploit 1

Other 3

  • TI-2023-10313 URI validation failure on SVG parsing. Bypass of CVE-2023-23924 CVSS 3.1CRITICAL 10.0
  • TI-2023-09722 URI validation failure on SVG parsing in Dompdf CVSS 3.1CRITICAL 10.0
  • TI-2021-02812 Improper Restriction of XML External Entity Reference in dompdf/dompdf CVSS 3.1CRITICAL 9.8
  • TI-2021-02769 PHAR Deserialization in dompdf/dompdf CVSS 3.1CRITICAL 9.8
  • TI-2024-16571 php-svg-lib lacks path validation on font through SVG inline styles CVSS 3.1CRITICAL 9.8
  • TI-2023-27479 php-svg-lib possible DoS caused by infinite recursion when parsing SVG document CVSS 3.1HIGH 7.5
See all 16 →

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences