CVE-2021-44521 — cassandra-all
CRITICALCVE-2021-44521 is a critical-severity (CVSS 9.1) Code Injection vulnerability in org.apache.cassandra:cassandra-all. 4 public exploit references exist, so weaponization risk is real. A fix is available for org.apache.cassandra:cassandra-all — see the affected versions and patch details below.
Apache Cassandra vulnerable to Code Injection due to unsafe configuration
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-2021-44521 plotted by exploitation likelihood (EPSS) against impact (CVSS). The shaded corner — EPSS 50%+ and CVSS 7.0+ — is where this CVE sits: patch-first territory.
Where this sits among everything scored
Of 376,715 CVEs with a current EPSS score, this one falls in the 50–90% band (highlighted). Real counts from FIRST.org, not a sample — log-scaled since the landscape is heavily right-skewed.
Real-World Exposure
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 | 3.0.26org.apache.cassandra:cassandra-all:3.0.26 |
| ☕Maven | org.apache.cassandra:cassandra-all | ≥ 3.11.0&&< 3.11.12 | 3.11.12org.apache.cassandra:cassandra-all:3.11.12 |
| ☕Maven | org.apache.cassandra:cassandra-all | ≥ 4.0.0&&< 4.0.2 | 4.0.2org.apache.cassandra:cassandra-all: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, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
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 Security's impact-aware SCA analyses which vulnerable code paths your application actually calls, so a match like CVE-2021-44521 can be triaged on real exposure rather than presence alone.
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 Security finds CVE-2021-44521 across Maven dependencies, including transitive ones, and its impact-aware SCA ranks findings by whether your code actually calls the vulnerable path.