dompdf/dompdf security advisory

CVE-2026-59943: Dompdf: Embedded SVG images can leak existence of files and directories within the filesystem

CVE-2026-59943 is a medium-severity security vulnerability in the PHP package dompdf/dompdf (CVSS 5.3), published 28 July 2026. It is fixed in 3.1.6; earlier versions are affected. It can be exploited without an account.

medium 5.3 published 2026-07-28 · updated 2026-08-04

Affected versions: < 3.1.6
Fixed in: 3.1.6
Newest release: 3.1.6
Severity: Medium · CVSS 5.3
Type: Security issue
CWE-209
Exploited in the wild: Not on the CISA KEV list
checked 2026-11-04

Is your dompdf/dompdf version affected?

Run composer show dompdf/dompdf in your project, then enter the version. We check it against this and every other known dompdf/dompdf advisory.

Who can exploit CVE-2026-59943

Access: No account. Anyone who can send a request to an app that uses the affected code.

CVSS vector (scored by NVD): CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N

Your app is only exposed if it uses the affected part of dompdf/dompdf. The advisory below says which part that is. If you are not sure, upgrade anyway: it costs less than finding out.

How to fix CVE-2026-59943 in dompdf/dompdf

Find the installed version: composer show dompdf/dompdf. If you never required it yourself, composer why dompdf/dompdf shows which package pulls it in.
Update it: composer update dompdf/dompdf --with-all-dependencies. You need 3.1.6 or newer.
If Composer will not go that high, your composer.json constraint is holding it back. Widen it (for example "dompdf/dompdf": "^3.1.6" if you can take that version), or upgrade the package that requires it.
Run composer audit. It reads the same advisory data and should no longer list CVE-2026-59943.
Commit composer.lock and deploy it. On the server, run composer install --no-dev from the lock file, not composer update.

If you cannot upgrade yet

General hardening for this kind of issue while the upgrade waits. None of it replaces the fix.

If your app does not use the affected feature, note that in your audit, but still plan the upgrade.

The CVE-2026-59943 advisory

Dompdf is an HTML to PDF converter for PHP. In versions 3.15 and prior, if a malicious actor can supply unrestricted content for rendering by Dompdf they can utilize the SVG rendering functionality to leak filesystem information when rendering PDF files using image references within a data-URI encoded SVG document. Using an <image> element inside a data-URI embedded SVG, an attacker can attempt to embed other files via the href or xlink:href attributes. When processing a file that does not exist (e.g. file:///DOESNOTEXIST), dompdf behaves differently than it does when accessing a file or directory that actually exists on the filesystem. This issue has been fixed in version 3.16.

Description from the CVE record, published by GitHub (the CVE Numbering Authority), via the NVD entry for CVE-2026-59943. Advisory title: “Dompdf: Embedded SVG images can leak existence of files and directories within the filesystem”.

References

GitHub advisory GHSA-j8qw-6jw8-r297 github.com
Fix commit 6a58996 github.com
Release v3.1.6 github.com

Other dompdf/dompdf advisories

medium CVE-2026-59942: Dompdf: Denial of Service (DoS) via Resource Exhaustion using Oversized Image Bitmaps 2026-07-22
medium CVE-2026-59941: Dompdf: Uncontrolled resource consumption based on declared BMP dimensions 2026-07-22
medium CVE-2026-56722: Dompdf: Local file read due to improper file path validation in SVG images encoded as data-URI 2026-07-22
low CVE-2026-55555: Dompdf: File existence oracle via font-face stylesheet declaration 2026-07-22
low CVE-2026-55554: Dompdf: Chroot Validation Bypass 2026-07-22
critical CVE-2021-3902: Improper Restriction of XML External Entity Reference in dompdf/dompdf 2024-11-15

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Where this data comes from

Affected and fixed versions: the Packagist security advisories API (GitHub Advisory Database and FriendsOfPHP), the same data composer audit uses. Synced 2026-11-03.
Description, score, weakness and references: NIST National Vulnerability Database (NVD), checked 2026-11-04. This product uses data from the NVD API but is not endorsed or certified by the NVD.
Exploited-in-the-wild status: the CISA Known Exploited Vulnerabilities catalog, checked 2026-11-04.
Compiled by Daniel Lasek at Laskyr from the sources above. The summary, “who can exploit it”, “how to fix it” and hardening sections are our plain-English reading of the record and are generated from it. The quoted description is the record's own text. Spot an error? Tell us.