GHSA-c4r9-r8fh-9vj2 — snakeyaml
MEDIUMGHSA-c4r9-r8fh-9vj2 is a medium-severity (CVSS 6.5) CWE-121 vulnerability in org.yaml:snakeyaml. A fix is available for org.yaml:snakeyaml — see the affected versions and patch details below.
snakeYAML before 1.31 vulnerable to Denial of Service due to Out-of-bounds Write
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
GHSA-c4r9-r8fh-9vj2 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 379,145 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.yaml:snakeyaml☕be.cylab:snakeyaml☕com.alipay.sofa.acts:acts-common-util☕io.prometheus.jmx:jmx_prometheus_httpserver☕io.prometheus.jmx:jmx_prometheus_httpserver_java6☕org.testifyproject.external:external-snakeyaml☕pl.droidsonroids.yaml:snakeyamlReal-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
Using snakeYAML to parse untrusted YAML files may be vulnerable to Denial of Service attacks (DOS). If the parser is running on user supplied input, an attacker may supply content that causes the parser to crash by stackoverflow.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| ☕Maven | org.yaml:snakeyaml | all versions | 1.31org.yaml:snakeyaml:1.31 |
| ☕Maven | be.cylab:snakeyaml | all versions | No fix |
| ☕Maven | com.alipay.sofa.acts:acts-common-util | all versions | No fix |
| ☕Maven | io.prometheus.jmx:jmx_prometheus_httpserver | all versions | No fix |
| ☕Maven | io.prometheus.jmx:jmx_prometheus_httpserver_java6 | all versions | No fix |
| ☕Maven | org.testifyproject.external:external-snakeyaml | 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.yaml:snakeyaml, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update org.yaml:snakeyaml to 1.31 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-c4r9-r8fh-9vj2 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 GHSA-c4r9-r8fh-9vj2 can be triaged on real exposure rather than presence alone.
Tailored to GHSA-c4r9-r8fh-9vj2. 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.
Red Hat Build of Quarkus is not affected by this issue as it already includes the fixed version. Satellite component Candlepin does not directly use snakeyaml, so it is not affected. Regardless, an update with the latest, unaffected snakeyaml version will be provided at next release.
| Product | Fixed in | Advisory |
|---|---|---|
| Red Hat AMQ Broker 7 | snakeyaml | RHSA-2022:8876 |
| Red Hat AMQ Clients | snakeyaml | RHSA-2023:7697 |
| Red Hat build of Eclipse Vert.x 4.3.3 | snakeyaml | RHSA-2022:6757 |
| Red Hat Data Grid 8.4.0 | snakeyaml | RHSA-2022:8524 |
| Red Hat Fuse 7.11.1 | snakeyaml | RHSA-2022:8652 |
| Red Hat Satellite 6.13 for RHEL 8 | candlepin-0:4.2.13-1.el8sat | RHSA-2023:2097 |
| Red Hat Single Sign-On 7 | snakeyaml | RHSA-2023:1049 |
| Red Hat Single Sign-On 7.6 for RHEL 7 | rh-sso7-keycloak-0:18.0.6-1.redhat_00001.1.el7sso | RHSA-2023:1043 |
Frequently Asked Questions
Is GHSA-c4r9-r8fh-9vj2 in your dependencies?
O3 Security finds GHSA-c4r9-r8fh-9vj2 across Maven dependencies, including transitive ones, and its impact-aware SCA ranks findings by whether your code actually calls the vulnerable path.