CVE-2021-3312 is a medium-severity (CVSS 6.5) XML External Entity (XXE) vulnerability in org.opencms:opencms-core. 1 public exploit reference exists, so weaponization risk is real. A fix is available for org.opencms:opencms-core — see the affected versions and patch details below.
XML External Entity Reference in org.opencms:opencms-core
EPSS Exploitation Probability
Probability of exploitation in the next 30 days, from FIRST.org EPSS.
How urgent is this, really
CVE-2021-3312 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
org.opencms:opencms-coreReal-time download stats are indexed for npm and PyPI packages. This vulnerability affects Maven packages — download data is not available via public APIs for these ecosystems.
Description
An XML external entity (XXE) vulnerability in Alkacon OpenCms 11.0, 11.0.1 and 11.0.2 allows remote authenticated users with edit privileges to exfiltrate files from the server's file system by uploading a crafted SVG document.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| ☕Maven | org.opencms:opencms-core | ≥ 11.0.0&&< 12.0.0 | 12.0.0org.opencms:opencms-core:12.0.0 |
Affected Products
opencmsalkaconResearch 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 org.opencms:opencms-core, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update org.opencms:opencms-core to 12.0.0 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2021-3312 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.
Frequently Asked Questions
Is CVE-2021-3312 in your dependencies?
Find it across Maven, including transitive dependencies.