Dompdf vulnerabilities

In Dompdf versions 3.15 and prior, if an attacker can supply unrestricted content for rendering, they can utilize SVG rendering to leak filesystem information. Using an <image> element inside a data-URI embedded SVG, an attacker can attempt to embed other files. The difference in behavior when accessing existing vs. non-existing files enables information disclosure. This issue is fixed in version 3.16.

In Dompdf versions 3.15 and prior, there is a Denial of Service (DoS) vulnerability via resource exhaustion. An attacker can submit a specially crafted HTML document with a single image of massive dimensions (e.g., 30,000x30,000 pixels), causing large memory and CPU allocation. This issue is fixed in version 3.16.

In Dompdf versions 3.15 and prior, a BMP image is accepted and a PDF-compatible PNG is generated based only on its declared header dimensions, without bounding width × height before conversion via GD. A small BMP (58 bytes) with a header declaring e.g. 6000×6000 causes full pixel canvas allocation, leading to significant memory amplification (up to 12x). This issue is fixed in version 3.16.

Dompdf versions 3.15 and earlier allow an attacker controlling HTML input to bypass restrictions by embedding a file path in an SVG image delivered via data: URI. During SVG processing, the second pass does not enforce the same protections as the first, leading to arbitrary image file reads from the server's filesystem.

Dompdf versions 3.15 and prior are vulnerable to a File Existence Oracle attack via manipulation of the CSS @font-face directive. An attacker can exploit the difference in behavior when referencing existing vs. non-existing local files (via file:// protocol) as an oracle to enumerate files on the server, even with CHROOT restrictions. This issue has been fixed in version 3.16.

In Dompdf versions 3.15 and prior, the validateLocalUri() method enforces CHROOT boundaries via a prefix check after path normalization. Because normalization strips the trailing directory separator, the check can be bypassed (e.g., /var/www also matches /var/www2). An attacker controlling part of the rendered HTML can read files outside the allowed directory. This issue has been fixed in version 3.16.