CVE-2026-55555
HighCVSS 7.5Exploitation Probability (EPSS)
Low risk40th percentile - higher than 40% of all known CVEs
Summary
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.
Risk Assessment
An attacker can determine which files exist on the server, potentially aiding further attacks (e.g., on configuration or sensitive data).
Recommendation
Upgrade Dompdf to version 3.16 or later.
Other vulnerabilities in Dompdf
See all- CVE-2026-59943Medium
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.
- CVE-2026-59942High
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.
- CVE-2026-59941High
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.
- CVE-2026-56722Medium
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.
- CVE-2026-55554High
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.
Original NVD description (English source)
Dompdf is an HTML to PDF converter for PHP. Versions 3.15 and prior are 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. Because Dompdf behaves differently depending on whether a referenced local file exists (an existing file is processed repeatedly until it triggers an "Allowed memory size exhausted" crash, whereas a missing file fails fast or is ignored and never hits the memory limit), an attacker can use this observable discrepancy as an oracle to enumerate sensitive files on the server regardless of CHROOT restrictions. Exploitation requires the attacker to supply unrestricted or unsanitized HTML in a request that permits large data, plus a configuration where Dompdf's memory limit is low enough to be exhausted (with $_dompdf_show_warnings=true making the overflow easier to reach). This issue has been fixed in version 3.16.