CVE-2021-44521
CRITICALApache Cassandra vulnerable to Code Injection due to unsafe configuration
Blast Radius
org.apache.cassandra:cassandra-all☕org.apache.cassandra:cassandra-all☕org.apache.cassandra:cassandra-allReal-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
When running Apache Cassandra with the following configuration: enable_user_defined_functions: true enable_scripted_user_defined_functions: true enable_user_defined_functions_threads: false it is possible for an attacker to execute arbitrary code on the host. The attacker would need to have enough permissions to create user defined functions in the cluster to be able to exploit this. Note that this configuration is documented as unsafe, and will continue to be considered unsafe after this CVE.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| ☕Maven | org.apache.cassandra:cassandra-all | all versions | 3.0.26 |
| ☕Maven | org.apache.cassandra:cassandra-all | ≥ 3.11.0&&< 3.11.12 | 3.11.12 |
| ☕Maven | org.apache.cassandra:cassandra-all | ≥ 4.0.0&&< 4.0.2 | 4.0.2 |
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 org.apache.cassandra:cassandra-all. 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 org.apache.cassandra:cassandra-all to 3.0.26 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2021-44521 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 CVE-2021-44521 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 CVE-2021-44521. 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-2021-44521 in your dependencies?
O3 detects CVE-2021-44521 across Maven dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.