CVE-2026-56722: Input Validation Flaw

Description

Dompdf is an HTML to PDF converter for PHP. In versions 3.15 and prior, aAn attacker who controls the HTML input can bypass this restriction by embedding a target file path inside an SVG image delivered through a data: URI, because dompdf processes the SVG twice and the second pass does not enforce the same protections as the first. When rendering, dompdf hands the SVG to the separate php-svg-lib library with external references forced on, and that library has no knowledge of the chroot directory, blocks only the phar:// scheme, and ultimately reads the referenced file with no path or protocol validation. This lets an external, unauthenticated attacker read arbitrary image files from the server's file system in the default configuration. This issue has been fixed in version 3.16.

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Weakness Type (CWE)

CWE-20 Improper Input Validation

References

Other References

https://github.com/dompdf/dompdf/commit/6a58996865db05d8fede748507e50ac4b8c5bfd0 https://github.com/dompdf/dompdf/commit/bf7b02f642e26007dedc5a22b3d6e15f9931120a https://github.com/dompdf/dompdf/releases/tag/v3.1.6 https://github.com/dompdf/dompdf/security/advisories/GHSA-cx96-42px-69fm

Frequently Asked Questions

What is CVE-2026-56722? +

Dompdf is an HTML to PDF converter for PHP. In versions 3.15 and prior, aAn attacker who controls the HTML input can bypass this restriction by embedding a target file path inside an SVG image delivered through a data: URI, because dompdf processes the SVG twice and the second pass does not enforce the same protections as the first. When rendering, dompdf hands the SVG to the separate php-svg-lib library with external references forced on, and that library has no knowledge of the chroot directory, blocks only the phar:// scheme, and ultimately reads the referenced file with no path or protocol validation. This lets an external, unauthenticated attacker read arbitrary image files from the server's file system in the default configuration. This issue has been fixed in version 3.16.

How do I check if I'm vulnerable to CVE-2026-56722? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

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