CVE-2022-23539 is a medium-severity (CVSS 5.9) Broken Cryptographic Algorithm vulnerability in jsonwebtoken. A fix is available for jsonwebtoken — see the affected versions and patch details below.
jsonwebtoken unrestricted key type could lead to legacy keys usage
Exploitation Status
No confirmed exploitation observed yet
- 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-2022-23539.
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-2022-23539 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
How broadly this vulnerability is actually deployed: weekly install volume shows current usage, and reverse-dependency count shows how many other packages break if it stays unpatched.
jsonwebtokennpmDescription
Overview
Versions <=8.5.1 of jsonwebtoken library could be misconfigured so that legacy, insecure key types are used for signature verification. For example, DSA keys could be used with the RS256 algorithm.
Am I affected?
You are affected if you are using an algorithm and a key type other than the combinations mentioned below
| Key type | algorithm |
|---|---|
| ec | ES256, ES384, ES512 |
| rsa | RS256, RS384, RS512, PS256, PS384, PS512 |
| rsa-pss | PS256, PS384, PS512 |
And for Elliptic Curve algorithms:
alg | Curve |
|---|---|
| ES256 | prime256v1 |
| ES384 | secp384r1 |
| ES512 | secp521r1 |
How do I fix it?
Update to version 9.0.0. This version validates for asymmetric key type and algorithm combinations. Please refer to the above mentioned algorithm / key type combinations for the valid secure configuration. After updating to version 9.0.0, If you still intend to continue with signing or verifying tokens using invalid key type/algorithm value combinations, you’ll need to set the allowInvalidAsymmetricKeyTypes option to true in the sign() and/or verify() functions.
Will the fix impact my users?
There will be no impact, if you update to version 9.0.0 and you already use a valid secure combination of key type and algorithm. Otherwise, use the allowInvalidAsymmetricKeyTypes option to true in the sign() and verify() functions to continue usage of invalid key type/algorithm combination in 9.0.0 for legacy compatibility.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 📦npm | jsonwebtoken | all versions | 9.0.0npm install jsonwebtoken@9.0.0 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for jsonwebtoken, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update jsonwebtoken to 9.0.0 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2022-23539 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-2022-23539 can be triaged on real exposure rather than presence alone.
Tailored to CVE-2022-23539. 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.
The jsonwebtoken package is a transitive dependency and is not used directly in any of the Red Hat products. Hence, the impact is set to Moderate.
| Product | Fixed in | Advisory |
|---|---|---|
| RHODF-4.12-RHEL-8 | odf4/mcg-core-rhel8:v4.12.3-4 | RHSA-2023:3265 |
Frequently Asked Questions
Is CVE-2022-23539 in your dependencies?
O3 Security finds CVE-2022-23539 across npm dependencies, including transitive ones, and its impact-aware SCA ranks findings by whether your code actually calls the vulnerable path.