Dompdf: File existence oracle via font-face stylesheet declaration

Exploitation

No confirmed exploitation recorded. Patch Next marks exploitation only from CISA KEV.

CVSS 4.0

2.3 · 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 · score source

EPSS

• CVE-2026-55555: 0.51% estimated exploitation activity in the next 30 days; percentile 43.45 (FIRST EPSS, 2026-11-03). This is a model estimate, not proof of exploitation or customer exposure.

As published by the source; long descriptions are shortened.

Description Dompdf is 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. The critical point of this flaw is the discrepancy in system behavior: 1. If the file exists: Dompdf attempts to process the local resource multiple times, leading to an "Allowed memory size exhausted" error, which crashes the creation. 2. If the file does NOT exist: The rendering engine fails quickly or ignores the import, and the memory limit is not reached. This discrepancy allows an attacker to enumerate sensitive files on the server, regardless of CHROOT restrictions. Some factors impact the ability of attackers to exploit the vulnerability: - The attacker must be allowed to provide unrestricted and/or unsanitized HTML content. - System parameters must be configured in such a way that Dompdf is able to generate a…

Published by the source

22 Jul 2026, 21:07 UTC

Last modified by the source

22 Jul 2026, 21:07 UTC

Source last checked

26 Oct 2026, 14:50 UTC

1. Revision 1 · created · 26 Oct 2026

   Published from ghsa record GHSA-7x2p-4jvh-6384

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# Patch Next advisory brief: CVE-2026-55555

Advisory: Dompdf: File existence oracle via font-face stylesheet declaration
IDs: CVE-2026-55555, GHSA-7x2p-4jvh-6384
Record: https://patchnext.com/advisories/cve-2026-55555 (revision 1, source checked 26 Oct 2026, 14:50 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: Low (CVSS 2.3)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: dompdf/dompdf 3.1.6. A vendor fix does not mean a deployment is fixed.

## Affected components
- Packagist dompdf/dompdf: affected < 3.1.6; fixed in 3.1.6

## Suggested inspection (read-only)
- Packagist dompdf/dompdf: check the installed version with your package manager.

## Supported action
Upgrade each affected component to a fixed version on its release line. For a transitive dependency, upgrade the parent package or add an override or constraint, then regenerate the lockfile. Redeploy every environment that ran an affected version.

## Required regression checks
- Run the test suite and a production build.
- Exercise the features that depend on dompdf/dompdf.
- Repeat the inspection and confirm that only fixed versions remain installed.

## Rollback considerations
- Keep the previous lockfile and deployment artifact. Rolling back reinstates the vulnerable version, so apply any documented mitigation while you fix forward.

## Unresolved questions
- Which deployments run an affected version?
- Exploitation status can change. Check again before lowering the priority.
- Mark the work resolved only after the fixed version is verified in production.

## Sources
- Verified: https://github.com/advisories/GHSA-7x2p-4jvh-6384 (GitHub-reviewed advisory GHSA-7x2p-4jvh-6384 lists affected ranges: Packagist dompdf/dompdf >=0 <3.1.6)

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