CVE-2021-4303 is a medium-severity (CVSS 6.1) Cross-site Scripting (XSS) vulnerability in xataface/xataface. A fix is available for xataface/xataface — see the affected versions and patch details below.
Xataface vulnerable to Cross-site Scripting
Exploitation Status
No confirmed exploitation observed yet
- 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 CVE-2021-4303.
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
CVE-2021-4303 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 378,156 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
xataface/xatafaceReal-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
A vulnerability, which was classified as problematic, has been found in shannah Xataface up to 2.x. Affected by this issue is the function testftp of the file install/install_form.js.php of the component Installer. The manipulation leads to cross site scripting. The attack may be launched remotely. The complexity of an attack is rather high. The exploitation is known to be difficult. Upgrading to version 3.0.0 is able to address this issue. The patch is identified as 94143a4299e386f33bf582139cd4702571d93bde. It is recommended to upgrade the affected component. VDB-217442 is the identifier assigned to this vulnerability. NOTE: Installer is disabled by default.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐘Packagist | xataface/xataface | all versions | 3.0.0composer require xataface/xataface:^3.0.0 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for xataface/xataface, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update xataface/xataface to 3.0.0 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2021-4303 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 CVE-2021-4303 can be triaged on real exposure rather than presence alone.
Tailored to CVE-2021-4303. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is CVE-2021-4303 in your dependencies?
O3 Security finds CVE-2021-4303 across Packagist dependencies, including transitive ones, and its impact-aware SCA ranks findings by whether your code actually calls the vulnerable path.