GHSA-3cw5-7cxw-v5qg is a critical-severity (CVSS 10) CWE-551 vulnerability in dompdf/dompdf. 3 public exploit references exist, so weaponization risk is real. A fix is available for dompdf/dompdf — see the affected versions and patch details below.
Dompdf vulnerable to URI validation failure on SVG parsing
Exploitation Status
Proof-of-concept exploit code exists
- CISA’s SSVC triage found public proof-of-concept exploit code for this CVE, though no confirmed active exploitation.
- CISA assesses this as automatable — exploitation doesn’t require manual, per-target effort, which raises the odds of mass scanning and opportunistic attacks.
Exploitation and automatability from CISA’s SSVC triage for GHSA-3cw5-7cxw-v5qg.
EPSS Exploitation Probability
EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.
How urgent is this, really
GHSA-3cw5-7cxw-v5qg plotted by exploitation likelihood (EPSS) against impact (CVSS). The shaded corner — EPSS 50%+ and CVSS 7.0+ — is where this CVE doesn't sit, though severity or exploitability alone can still warrant action.
Where this sits among everything scored
Of 377,166 CVEs with a current EPSS score, this one falls in the < 10% band (highlighted). Real counts from FIRST.org, not a sample — log-scaled since the landscape is heavily right-skewed.
Real-World Exposure
dompdf/dompdfReal-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
The URI validation on dompdf 2.0.1 can be bypassed on SVG parsing by passing <image> tags with uppercase letters. This might leads to arbitrary object unserialize on PHP < 8, through the phar URL wrapper.
Details
The bug occurs during SVG parsing of <image> tags, in src/Image/Cache.php :
if ($type === "svg") {
$parser = xml_parser_create("utf-8");
xml_parser_set_option($parser, XML_OPTION_CASE_FOLDING, false);
xml_set_element_handler(
$parser,
function ($parser, $name, $attributes) use ($options, $parsed_url, $full_url) {
if ($name === "image") {
$attributes = array_change_key_case($attributes, CASE_LOWER);
This part will try to detect <image> tags in SVG, and will take the href to validate it against the protocolAllowed whitelist. However, the `$name comparison with "image" is case sensitive, which means that such a tag in the SVG will pass :
<svg>
<Image xlink:href="phar:///foo"></Image>
</svg>
As the tag is named "Image" and not "image", it will not pass the condition to trigger the check.
A correct solution would be to strtolower the $name before the check :
if (strtolower($name) === "image") {
PoC
Parsing the following SVG file is sufficient to reproduce the vulnerability :
<svg>
<Image xlink:href="phar:///foo"></Image>
</svg>
Impact
An attacker might be able to exploit the vulnerability to call arbitrary URL with arbitrary protocols, if they can provide a SVG file to dompdf. 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
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐘Packagist | dompdf/dompdf | all versions | 2.0.2composer require dompdf/dompdf:^2.0.2 |
Research use only. For defensive security, authorized penetration testing, and academic research only. Never execute exploit code against systems without explicit written authorization.
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for dompdf/dompdf, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update dompdf/dompdf to 2.0.2 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-3cw5-7cxw-v5qg 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 Security's impact-aware SCA analyses which vulnerable code paths your application actually calls, so a match like GHSA-3cw5-7cxw-v5qg can be triaged on real exposure rather than presence alone.
Tailored to GHSA-3cw5-7cxw-v5qg. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is GHSA-3cw5-7cxw-v5qg in your dependencies?
O3 Security finds GHSA-3cw5-7cxw-v5qg across Packagist dependencies, including transitive ones, and its impact-aware SCA ranks findings by whether your code actually calls the vulnerable path.