CVE-2023-51774 is a high-severity (CVSS 8.4) CWE-284 vulnerability in json-jwt. A fix is available for json-jwt — see the affected versions and patch details below.
json-jwt allows bypass of identity checks via a sign/encryption confusion attack
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 CVE-2023-51774.
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-2023-51774 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 377,636 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
json-jwt💎json-jwtReal-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
The json-jwt (aka JSON::JWT) gem 1.16.x before 1.16.6, 1.15.x before 1.15.3.1 for Ruby sometimes allows bypass of identity checks via a sign/encryption confusion attack. For example, JWE can sometimes be used to bypass JSON::JWT.decode.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 💎RubyGems | json-jwt | ≥ 1.16.0&&< 1.16.6 | 1.16.6bundle update json-jwt --conservative |
| 💎RubyGems | json-jwt | all versions | 1.15.3.1bundle update json-jwt --conservative |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for json-jwt, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update json-jwt to 1.16.6 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2023-51774 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-2023-51774 can be triaged on real exposure rather than presence alone.
Tailored to CVE-2023-51774. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is CVE-2023-51774 in your dependencies?
O3 Security finds CVE-2023-51774 across RubyGems dependencies, including transitive ones, and its impact-aware SCA ranks findings by whether your code actually calls the vulnerable path.