CVE-2015-6420 — commons-collections4
CVE-2015-6420 is a Deserialization of Untrusted Data vulnerability in org.apache.commons:commons-collections4. EPSS puts its 30-day exploitation probability at 18.6% (97th percentile). A fix is available for org.apache.commons:commons-collections4 — see the affected versions and patch details below.
Insecure Deserialization in Apache Commons Collection
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.
Real-World Exposure
org.apache.commons:commons-collections4☕commons-collections:commons-collections☕net.sourceforge.collections:collections-generic☕org.apache.servicemix.bundles:org.apache.servicemix.bundles.collections-generic☕org.apache.servicemix.bundles:org.apache.servicemix.bundles.commons-collectionsReal-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
Serialized-object interfaces in Java applications using the Apache Commons Collections (ACC) library may allow remote attackers to execute arbitrary commands via a crafted serialized Java object.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| ☕Maven | org.apache.commons:commons-collections4 | all versions | 4.1org.apache.commons:commons-collections4:4.1 |
| ☕Maven | commons-collections:commons-collections | all versions | 3.2.2commons-collections:commons-collections:3.2.2 |
| ☕Maven | net.sourceforge.collections:collections-generic | all versions | No fix |
| ☕Maven | org.apache.servicemix.bundles:org.apache.servicemix.bundles.collections-generic | all versions | No fix |
| ☕Maven | org.apache.servicemix.bundles:org.apache.servicemix.bundles.commons-collections | all versions | No fix |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for org.apache.commons:commons-collections4, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update org.apache.commons:commons-collections4 to 4.1 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2015-6420 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-2015-6420 can be triaged on real exposure rather than presence alone.
Tailored to CVE-2015-6420. 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-2015-6420 in your dependencies?
O3 Security finds CVE-2015-6420 across Maven dependencies, including transitive ones, and its impact-aware SCA ranks findings by whether your code actually calls the vulnerable path.