CVE-2026-45205 is a medium-severity (CVSS 5.3) CWE-674 vulnerability in org.apache.commons:commons-configuration2. A fix is available for org.apache.commons:commons-configuration2 — see the affected versions and patch details below.
Apache Commons Configuration: StackOverflowError for YAML input with cycles
Exploitation Status
No confirmed exploitation observed yet
- CISA assesses this as automatable — exploitation doesn’t require manual, per-target effort, which raises the odds of mass scanning and opportunistic attacks.
- CISA’s own triage has not observed active exploitation or public proof-of-concept code for this CVE as of its last assessment.
Exploitation and automatability from CISA’s SSVC triage for CVE-2026-45205.
EPSS Exploitation Probability
Probability of exploitation in the next 30 days, from FIRST.org EPSS.
How urgent is this, really
Where this sits among everything scored
Real-World Exposure
org.apache.commons:commons-configuration2Real-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
Uncontrolled Recursion vulnerability in Apache Commons.
When processing an untrusted configuration file, Commons Configuration will throw a StackOverflowError for YAML input with cycles. This issue affects Apache Commons: from 2.2 before 2.15.0.
Users are recommended to upgrade to version 2.15.0, which fixes the issue.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| ☕Maven | org.apache.commons:commons-configuration2 | ≥ 2.2&&< 2.15.0 | 2.15.0org.apache.commons:commons-configuration2:2.15.0 |
Affected Products
commons configurationapacheDetection & 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-configuration2, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update org.apache.commons:commons-configuration2 to 2.15.0 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-45205 is resolved across your whole dependency graph.
Workarounds
Stop feeding it untrusted input: reject or quarantine files and payloads from unverified sources until you can upgrade, restrict accepted formats to the ones you actually need, and run the parsing or decoding step in a least-privileged sandbox or short-lived worker so a crash or corrupted read cannot reach the rest of the process.
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.
This Important flaw in Apache Commons Configuration allows a remote attacker to trigger a denial of service by providing specially crafted YAML input containing cycles. This can lead to an uncontrolled recursion and a StackOverflowError, impacting the availability of systems that process untrusted YAML configuration…
To mitigate this issue, restrict Apache Commons Configuration to process only trusted YAML configuration files. Implement strict input validation for any YAML content originating from untrusted sources to prevent the parsing of malformed input with cyclical references. This operational control reduces the exposure to denial of service attacks.Source: Red Hat security advisory for CVE-2026-45205 (CC BY 4.0)
| Product | Fixed in | Advisory |
|---|---|---|
| Red Hat AMQ Broker 7.13.6 | commons-configuration2 | RHSA-2026:66545 |
| Red Hat AMQ Broker 7.14.1 | commons-configuration2 | RHSA-2026:66488 |
| Red Hat build of Apache Camel 4.18.3 for Spring Boot 3.5.16 | commons-configuration2 | RHSA-2026:54622 |
Frequently Asked Questions
Is CVE-2026-45205 in your dependencies?
Find it across Maven, including transitive dependencies.