Dompdf: Uncontrolled resource consumption based on declared BMP dimensions

Exploitation

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

CVSS 4.0

6.3 · CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N · score source

EPSS

• CVE-2026-59941: 0.64% estimated exploitation activity in the next 30 days; percentile 50.92 (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.

Summary dompdf accepts a BMP image and generates a PDF-compatible PNG based only on its declared header dimensions and never bounds width × height before the image is converted through GD. A 58-byte BMP whose header declares e.g. 6000×6000 is accepted and later drives imagecreatetruecolor($width, $height) (and PHP's native BMP decoder) to allocate the full pixel canvas. A payload can fit in a single HTTP request: the BMP can be inlined as a data:image/bmp;base64,… URI inside attacker-controlled HTML, so no upload, no remote fetch, and no chroot-reachable file is required. It was demonstrated that a 169-byte request drove dompdf to render to ~412 MB peak RSS and ~4.8 s of CPU/wall time, versus ~34 MB for an identically-sized benign request — roughly a 12× memory amplification per request, repeatable and unauthenticated. Details Root cause The image is processed based on declared dimensions and type alone — no pixel budget: For BMPs that getimagesize() does not fully parse, dompdf…

Published by the source

22 Jul 2026, 22:50 UTC

Last modified by the source

22 Jul 2026, 22:50 UTC

Source last checked

26 Oct 2026, 14:50 UTC

1. Revision 1 · created · 26 Oct 2026

   Published from ghsa record GHSA-8hg6-c449-896m

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# Patch Next advisory brief: CVE-2026-59941

Advisory: Dompdf: Uncontrolled resource consumption based on declared BMP dimensions
IDs: CVE-2026-59941, GHSA-8hg6-c449-896m
Record: https://patchnext.com/advisories/cve-2026-59941 (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: Medium (CVSS 6.3)
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-8hg6-c449-896m (GitHub-reviewed advisory GHSA-8hg6-c449-896m lists affected ranges: Packagist dompdf/dompdf >=0 <3.1.6)

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