GHSA-977c-63xq-cgw3 is a high-severity (CVSS 8.8) Deserialization of Untrusted Data vulnerability in opensearch-ruby. 1 public exploit reference exists, so weaponization risk is real. A fix is available for opensearch-ruby — see the affected versions and patch details below.
opensearch-ruby 2.x before 2.0.2 vulnerable to unsafe YAML deserialization
Exploitation Status
Proof-of-concept exploit code exists
- CISA’s SSVC triage found public proof-of-concept exploit code for this CVE, though no confirmed active exploitation.
- A successful exploit gives an attacker total control of the affected component, not partial access.
Exploitation and automatability from CISA’s SSVC triage for GHSA-977c-63xq-cgw3.
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-977c-63xq-cgw3 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 377,333 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
opensearch-rubyReal-time download stats are indexed for npm and PyPI packages. This vulnerability affects RubyGems packages — download data is not available via public APIs for these ecosystems.
Description
Impact
A YAML deserialization in opensearch-ruby 2.0.0 can lead to unsafe deserialization using YAML.load if the response is of type YAML.
Patches
The problem has been patched in opensearch-ruby gem version 2.0.2.
Workarounds
No viable workaround. Please upgrade to 2.0.2
References
https://github.com/opensearch-project/opensearch-ruby/pull/77 https://staaldraad.github.io/post/2021-01-09-universal-rce-ruby-yaml-load-updated/
For more information
If you have any questions or comments about this advisory:
- Open an issue in opensearch-ruby
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 💎RubyGems | opensearch-ruby | ≥ 2.0.0&&< 2.0.2 | 2.0.2bundle update opensearch-ruby --conservative |
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 opensearch-ruby, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update opensearch-ruby to 2.0.2 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-977c-63xq-cgw3 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-977c-63xq-cgw3 can be triaged on real exposure rather than presence alone.
Tailored to GHSA-977c-63xq-cgw3. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is GHSA-977c-63xq-cgw3 in your dependencies?
O3 Security finds GHSA-977c-63xq-cgw3 across RubyGems dependencies, including transitive ones, and its impact-aware SCA ranks findings by whether your code actually calls the vulnerable path.