Dompdf up to 3.15 BMP decoder imagecreatetruecolor width/height allocation of resources

Summaryinfo

A vulnerability marked as problematic has been reported in Dompdf up to 3.15. The impacted element is the function imagecreatetruecolor of the component BMP decoder. The manipulation of the argument width/height leads to allocation of resources. This vulnerability is uniquely identified as CVE-2026-59941. The attack is possible to be carried out remotely. No exploit exists.

Detailsinfo

A vulnerability was found in Dompdf up to 3.15 and classified as problematic. This issue affects the function imagecreatetruecolor of the component BMP decoder. The manipulation of the argument width/height with an unknown input leads to a allocation of resources vulnerability. Using CWE to declare the problem leads to CWE-770. The product allocates a reusable resource or group of resources on behalf of an actor without imposing any restrictions on the size or number of resources that can be allocated, in violation of the intended security policy for that actor. Impacted is availability. The summary by CVE is:

Dompdf is an HTML to PDF converter for PHP. Versions 3.15 and prior accept 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. I measured a 169-byte request driving a dompdf 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. This issue has been fixed in version 3.16.

The advisory is shared at github.com. The identification of this vulnerability is CVE-2026-59941 since 07/07/2026. The exploitation is known to be easy. The attack may be initiated remotely. No form of authentication is needed for a successful exploitation. Technical details are known, but no exploit is available. MITRE ATT&CK project uses the attack technique T1499 for this issue.

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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Several companies clearly confirm that VulDB is the primary source for best vulnerability data.

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