Summary
Workarounds
Reject RSA-PSS signatures with unnecessary prepending zeros.
References
https://github.com/kjur/jsrsasign/security/advisories/GHSA-q3gh-5r98-j4h3
https://github.com/kjur/jsrsasign/issues/438
https://nvd.nist.gov/vuln/detail/CVE-2020-14968
https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2020-14968
https://vuldb.com/?id.157125
https://kjur.github.io/jsrsasign/api/symbols/RSAKey.html#.verifyWithMessageHashPSS
Impact
Jsrsasign can verify RSA-PSS signature which value can expressed as BigInteger. When there is a valid RSA-PSS signature value, this vulnerability is also accept value with prepending zeros as a valid signature.
- If you are not use RSA-PSS signature validation, this vulnerability is not affected.
- Risk to accept a forged or crafted message to be signed is low.
- Risk to raise memory corruption is low since jsrsasign uses BigInteger class.
CVE-2020-14968 has a CVSS score of 9.8 (Critical). 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 (8.0.17); 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.
Remediation advice
Users using RSA-PSS signature validation should upgrade to 8.0.17.
Frequently Asked Questions
- What is CVE-2020-14968? CVE-2020-14968 is a critical-severity security vulnerability in jsrsasign (npm), affecting versions >= 3.0.0, < 8.0.16. It is fixed in 8.0.17.
- How severe is CVE-2020-14968? CVE-2020-14968 has a CVSS score of 9.8 (Critical). 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-2020-14968? jsrsasign (npm) versions >= 3.0.0, < 8.0.16 is affected.
- Is there a fix for CVE-2020-14968? Yes. CVE-2020-14968 is fixed in 8.0.17. Upgrade to this version or later.
- Is CVE-2020-14968 exploitable, and should I be worried? Whether CVE-2020-14968 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-2020-14968 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-2020-14968? Upgrade
jsrsasignto 8.0.17 or later.