CVE-2021-39170 is a medium-severity (CVSS 5.4) CWE-116 vulnerability in pimcore/pimcore. 1 public exploit reference exists, so weaponization risk is real. A fix is available for pimcore/pimcore — see the affected versions and patch details below.
Improper Encoding or Escaping of Output in Asset Metadata Component
EPSS Exploitation Probability
Probability of exploitation in the next 30 days, from FIRST.org EPSS.
How urgent is this, really
CVE-2021-39170 by exploitation likelihood (EPSS) against impact (CVSS). Outside the shaded patch-first corner.
Where this sits among everything scored
Of 385,738 CVEs with a current EPSS score, this one falls in the < 10% band (highlighted). Counts from FIRST.org, log-scaled.
Real-World Exposure
pimcore/pimcoreReal-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
Pimcore is an open source data & experience management platform. Prior to version 10.1.2, an authenticated user could add XSS code as a value of custom metadata on assets. There is a patch for this issue in Pimcore version 10.1.2. As a workaround, users may apply the patch manually.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐘Packagist | pimcore/pimcore | all versions | 10.1.2composer require pimcore/pimcore:^10.1.2 |
Affected Products
pimcorepimcoreResearch 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 pimcore/pimcore, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update pimcore/pimcore to 10.1.2 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2021-39170 is resolved across your whole dependency graph.
Workarounds
Escape or sanitise the affected output on the server side rather than relying on client-side filtering, and add a Content-Security-Policy that blocks inline script execution so injected markup cannot run even if it reaches the page.
Frequently Asked Questions
Is CVE-2021-39170 in your dependencies?
Find it across Packagist, including transitive dependencies.