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Vulnerability record · CVE-2020-14966 · published 22 June 2020

CVE-2020-14966: Kjur jsrsasign improper verification of cryptographic signature vulnerability

Kjur · Jsrsasign

An issue was discovered in the jsrsasign package through 8.0.18 for Node.js. It allows a malleability in ECDSA signatures by not checking overflows in the length of a sequence and '0' characters appended or prepended to an integer. The modified signatures are verified as valid. This could have a security-relevant impact if an application relied on a single canonical signature.

7.5 CVSS 3.1 High EPSS 1.1% · top 35.1% CWE-347 · Improper verification of cryptographic signature
7.5CVSS 3.1 base score, v2 5.0
1.1%EPSS exploitation probability, 30 days
NoNot in CISA KEV
2Affected product versions listed by NVD
12References, 2 tagged exploit
22 Jun 2026Last modified by NVD

Description

An issue was discovered in the jsrsasign package through 8.0.18 for Node.js. It allows a malleability in ECDSA signatures by not checking overflows in the length of a sequence and '0' characters appended or prepended to an integer. The modified signatures are verified as valid. This could have a security-relevant impact if an application relied on a single canonical signature.

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N

Affected products

2 vulnerable configurations from NVD's CPE data, grouped by vendor and product.

References

LinkTags
https://github.com/kjur/jsrsasign/issues/437 ExploitIssue TrackingThird Party Advisory
https://github.com/kjur/jsrsasign/releases/tag/8.0.17 Release NotesThird Party Advisory
https://github.com/kjur/jsrsasign/releases/tag/8.0.18 Release NotesThird Party Advisory
https://kjur.github.io/jsrsasign/ Release NotesThird Party Advisory
https://security.netapp.com/advisory/ntap-20200724-0001/ Third Party Advisory
https://www.npmjs.com/package/jsrsasign ProductThird Party Advisory
https://github.com/kjur/jsrsasign/issues/437 ExploitIssue TrackingThird Party Advisory
https://github.com/kjur/jsrsasign/releases/tag/8.0.17 Release NotesThird Party Advisory
https://github.com/kjur/jsrsasign/releases/tag/8.0.18 Release NotesThird Party Advisory
https://kjur.github.io/jsrsasign/ Release NotesThird Party Advisory
https://security.netapp.com/advisory/ntap-20200724-0001/ Third Party Advisory
https://www.npmjs.com/package/jsrsasign ProductThird Party Advisory

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Related vulnerabilities

Same products first, then exploited flaws of the same weakness class.

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Source: NIST National Vulnerability Database (record CVE-2020-14966), CISA KEV, FIRST EPSS (scores of 2026-09-28). This page is refreshed as NVD updates the record.