GHSA-2p3x-qw9c-25hh
HIGHGHSA-2p3x-qw9c-25hh is a high-severity (CVSS 7.5) Uncontrolled Resource Consumption vulnerability in com.thoughtworks.xstream:xstream. 1 public exploit reference exists, so weaponization risk is real. O3 Security confirms whether GHSA-2p3x-qw9c-25hh is actually reachable in your code before you act, and blocks exploitation at runtime until you patch.
XStream can cause a Denial of Service.
Real-World Exposure
com.thoughtworks.xstream:xstreamReal-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
Impact
The vulnerability may allow a remote attacker to allocate 100% CPU time on the target system depending on CPU type or parallel execution of such a payload resulting in a denial of service only by manipulating the processed input stream. No user is affected, who followed the recommendation to setup XStream's security framework with a whitelist limited to the minimal required types.
Patches
If you rely on XStream's default blacklist of the Security Framework, you will have to use at least version 1.4.16.
Workarounds
See workarounds for the different versions covering all CVEs.
References
See full information about the nature of the vulnerability and the steps to reproduce it in XStream's documentation for CVE-2021-21341.
Credits
The vulnerability was discovered and reported by threedr3am.
For more information
If you have any questions or comments about this advisory:
- Open an issue in XStream
- Contact us at XStream Google Group
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| ☕Maven | com.thoughtworks.xstream:xstream | all versions | 1.4.16 |
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 com.thoughtworks.xstream:xstream. 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 com.thoughtworks.xstream:xstream to 1.4.16 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-2p3x-qw9c-25hh 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 GHSA-2p3x-qw9c-25hh 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 GHSA-2p3x-qw9c-25hh. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Fixing This On Your OS
If you run this on a Linux distribution, patch through your package manager against the distro's own security advisory below — it tracks the exact backported fix for your release, which can ship on a different timeline (and sometimes a different severity) than the upstream project.
OpenShift Container Platform (OCP) delivers Jenkins LTS package with bundled XStream library. Due to JEP-200 [1] and JEP-228 [2] Jenkins projects, OCP Jenkins package is not affected by this flaw. [1] https://github.com/jenkinsci/jep/blob/master/jep/200/README.adoc [2]…
Frequently Asked Questions
Is GHSA-2p3x-qw9c-25hh in your dependencies?
O3 detects GHSA-2p3x-qw9c-25hh across Maven dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.