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
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-2026-45205 plotted by exploitation likelihood (EPSS) against impact (CVSS). The shaded corner — EPSS 50%+ and CVSS 7.0+ — is where this CVE doesn't sit, though severity or exploitability alone can still warrant action.
Where this sits among everything scored
Of 378,567 CVEs with a current EPSS score, this one falls in the < 10% band (highlighted). Real counts from FIRST.org, not a sample — log-scaled since the landscape is heavily right-skewed.
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 |
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-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
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-2026-45205 can be triaged on real exposure rather than presence alone.
Tailored to CVE-2026-45205. 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.
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…
| 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?
O3 Security finds CVE-2026-45205 across Maven dependencies, including transitive ones, and its impact-aware SCA ranks findings by whether your code actually calls the vulnerable path.