CVE-2021-36787 is a medium-severity (CVSS 5.4) Cross-site Scripting (XSS) vulnerability in in2code/femanager. 2 public exploit references exist, so weaponization risk is real. A fix is available for in2code/femanager — see the affected versions and patch details below.
Cross-site Scripting in the femanager TYPO3 extension
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-2021-36787 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 378,567 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
in2code/femanager🐘in2code/femanagerReal-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
The extension allows by default to upload SVG files when a logged in frontend user uploads a new profile image. This may lead to Cross-Site Scripting, when the uploaded SVG image is used as is on the website.
Note: If SVG uploads are required, it is recommended to use the TYPO3 extension svg_sanitizer (added to TYPO3 core since versions 9.5.28, 10.4.18 and 11.3.0) to prevent upload of malicious SVG files or to set up a strict Content Security Policy for the destination folder of uploaded images.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐘Packagist | in2code/femanager | all versions | 5.5.1composer require in2code/femanager:^5.5.1 |
| 🐘Packagist | in2code/femanager | ≥ 6.0.0&&< 6.3.1 | 6.3.1composer require in2code/femanager:^6.3.1 |
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 in2code/femanager, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update in2code/femanager to 5.5.1 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2021-36787 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-2021-36787 can be triaged on real exposure rather than presence alone.
Tailored to CVE-2021-36787. 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-2021-36787 in your dependencies?
O3 Security finds CVE-2021-36787 across Packagist dependencies, including transitive ones, and its impact-aware SCA ranks findings by whether your code actually calls the vulnerable path.