Summary
JWS and JWT signature validation vulnerability with special characters
Workarounds
Validate JWS or JWT signature if it has Base64URL and dot safe string before
executing JWS.verify() or JWS.verifyJWT() method.
ACKNOWLEDGEMENT
Thanks to Adi Malyanker and Or David for this vulnerability report. Also thanks for Snyk security team for this coordination.
References
https://github.com/kjur/jsrsasign/releases/tag/10.5.25
https://github.com/kjur/jsrsasign/security/advisories/GHSA-3fvg-4v2m-98jf kjur's advisories
https://github.com/advisories/GHSA-3fvg-4v2m-98jf github advisories
https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2022-25898
https://kjur.github.io/jsrsasign/api/symbols/KJUR.jws.JWS.html#.verifyJWT
https://kjur.github.io/jsrsasign/api/symbols/KJUR.jws.JWS.html#.verify
https://kjur.github.io/jsrsasign/api/symbols/global__.html#.isBase64URLDot
https://github.com/kjur/jsrsasign/wiki/Tutorial-for-JWS-verification
https://github.com/kjur/jsrsasign/wiki/Tutorial-for-JWT-verification
https://security.snyk.io/vuln/SNYK-JS-JSRSASIGN-2869122
Impact
Jsrsasign supports JWS(JSON Web Signatures) and JWT(JSON Web Token) validation. However JWS or JWT signature with non Base64URL encoding special characters or number escaped characters may be validated as valid by mistake.
For example, even if a string of non Base64URL encoding characters such as !@$% or \11 is inserted into a valid JWS or JWT signature value string, it will still be a valid JWS or JWT signature by mistake.
When jsrsasign's JWS or JWT validation is used in OpenID connect or OAuth2, this vulnerability will affect to authentication or authorization.
By our internal assessment, CVSS 3.1 score will be 8.6.
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:H/A:N
CVE-2022-25898 has a CVSS score of 8.6 (High). The vector is network-reachable, no privileges required, and no user interaction. A CVSS score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether this affects your application depends on whether the vulnerable code is present and reachable in your environment. A fixed version is available (10.5.25); upgrading removes the vulnerable code path.
Affected versions
Security releases
Kodem intelligence
Severity tells you how bad this could be in the worst case. It does not tell you whether you are exposed. Exploitability and impact are functions of runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A vulnerable package can sit in your dependency tree and never run.
Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter. Kodem's runtime-powered SCA identifies whether this CVE is reachable in your applications.
Already deployed Kodem?
See it in your environmentNew to Kodem? Get a demo →Remediation advice
Users validate JWS or JWT signatures should upgrade to 10.5.25.
Frequently Asked Questions
- What is CVE-2022-25898? CVE-2022-25898 is a high-severity security vulnerability in jsrsasign (npm), affecting versions >= 4.8.0, < 10.5.25. It is fixed in 10.5.25.
- How severe is CVE-2022-25898? CVE-2022-25898 has a CVSS score of 8.6 (High). This score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether it represents real risk in your environment depends on whether the vulnerable code is present and reachable.
- Which versions of jsrsasign are affected by CVE-2022-25898? jsrsasign (npm) versions >= 4.8.0, < 10.5.25 is affected.
- Is there a fix for CVE-2022-25898? Yes. CVE-2022-25898 is fixed in 10.5.25. Upgrade to this version or later.
- Is CVE-2022-25898 exploitable, and should I be worried? Whether CVE-2022-25898 is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk. Get a demo
- What actually determines whether CVE-2022-25898 is exploitable, and how bad it is? Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.
- How do I fix CVE-2022-25898? Upgrade
jsrsasignto 10.5.25 or later.