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TI-2026-40099 Aliases CVE-2026-55555GHSA-7x2p-4jvh-6384

Dompdf: File existence oracle via font-face stylesheet declaration

Priority MEDIUM 45CWE-203Published · 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-203.

Summary

Dompdf is an HTML to PDF converter for PHP. Versions 3.15 and prior are vulnerable to a File Existence Oracle attack through the manipulation of the CSS @font-face directive. By providing malicious HTML that references local files via the file:// protocol repeatedly, an attacker can trigger PHP memory exhaustion. Because Dompdf behaves differently depending on whether a referenced local file exists (an existing file is processed repeatedly until it triggers an "Allowed memory size exhausted" crash, whereas a missing file fails fast or is ignored and never hits the memory limit), an attacker can use this observable discrepancy as an oracle to enumerate sensitive files on the server regardless of CHROOT restrictions. Exploitation requires the attacker to supply unrestricted or unsanitized HTML in a request that permits large data, plus a configuration where Dompdf's memory limit is low enough to be exhausted (with  $_dompdf_show_warnings=true  making the overflow easier to reach). This issue has been fixed in version 3.16.

Why it matters now

Exploitation Proof of concept CISA SSVC · not in CISA KEV
EPSS 0.00508 43rd 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-7x2p-4jvh-6384
  • 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-7x2p-4jvh-6384

CPE configurations NVD · 1

CPEVersionsRoleVendor
cpe:2.3:a:dompdf_project:dompdf:*:*:*:*:*:*:*:*before 3.16VulnerableDompdf Project
  • cpe:2.3:a:dompdf_project:dompdf:*:*:*:*:*:*:*:* Versions before 3.16 Vulnerable ·Dompdf Project

Remediation

  • Fix · CNA dompdf (dompdf) Fixed in 3.1.6
  • Fix · GHSA-7x2p-4jvh-6384 dompdf/dompdf (Packagist) Fixed in 3.1.6 Advisory →

Timeline

  1. 2026-10-02 Threatist record created from CVE-2026-55555
  2. 2026-10-03 Alias added: GHSA-7x2p-4jvh-6384

References

Exploit 1

Patch 1

Other 2

  • 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