GHSA-c5fp-p67m-gq56
GHSA-c5fp-p67m-gq56 is a Server-Side Request Forgery (SSRF) vulnerability in knplabs/knp-snappy. O3 Security confirms whether GHSA-c5fp-p67m-gq56 is actually reachable in your code before you act, and blocks exploitation at runtime until you patch.
Snappy : SSRF and local file read via the xsl-style-sheet option
Exploitation Status
No confirmed exploitation observed yet
- CISA assesses this as automatable — exploitation doesn’t require manual, per-target effort, which raises the odds of mass scanning and opportunistic attacks.
- CISA’s own triage has not observed active exploitation or public proof-of-concept code for this CVE as of its last assessment.
Exploitation and automatability from CISA’s SSVC triage for GHSA-c5fp-p67m-gq56.
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.
Real-World Exposure
knplabs/knp-snappyReal-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
Impact
It impacts applications where:
- the PHP daemon run with root permissions ;
- the application is either running outside a container or has sensitive file access ;
It could happens with this kind of workflows:
$stylesheet = $_GET['stylesheet']; // = ‘file:///etc/passwd’
$pdf = new Knp\Snappy\Pdf(‘/usr/local/bin/wkhtmltopdf’);
$pdf->generate(‘page.html’, ‘out.pdf’, [
‘xsl-style-sheet’ => $stylesheet
]);
Patches
A list a schema with http and https by default is used to validate the remote path by default.
Workarounds
Developers should ensure usage cannot allow (in any case) a user to pass a free input directly to the Snappy library.
// Bad example
$pdf = new Knp\Snappy\Pdf(‘/usr/local/bin/wkhtmltopdf’);
$pdf->generate(‘page.html’, ‘out.pdf’, [
‘xsl-style-sheet’ => $_GET['input'],
]);
Instead developers can list available available stylesheets and pick the right one with the user input.
// Better
$allowedStylesheets = [
'invoice' => '/app/xsl/invoice.xsl',
'report' => '/app/xsl/report.xsl',
];
$key = $_GET['stylesheet'] ?? '';
if (!array_key_exists($key, $allowedStylesheets)) {
throw new \RuntimeException('Unknown stylesheet.');
}
$pdf = new Knp\Snappy\Pdf('/usr/local/bin/wkhtmltopdf');
$pdf->generate('page.html', 'out.pdf', [
'xsl-style-sheet' => $allowedStylesheets[$key],
]);
References
Read more about SSRF at owasp.org/www-community/attacks/Server_Side_Request_Forgery
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐘Packagist | knplabs/knp-snappy | all versions | 1.7.0 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for knplabs/knp-snappy. 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 knplabs/knp-snappy to 1.7.0 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-c5fp-p67m-gq56 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-c5fp-p67m-gq56 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-c5fp-p67m-gq56. 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-c5fp-p67m-gq56 in your dependencies?
O3 detects GHSA-c5fp-p67m-gq56 across Packagist dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.