RSA PKCS#1 decryption vulnerability with prepending zeros in jsrsasign
Impact
Jsrsasign supports RSA PKCS#1 v1.5 (i.e. RSAES-PKCS1-v1_5) and RSA-OAEP encryption and decryption. Its encrypted message is represented as BigInteger. When there is a valid encrypted message, a crafted message with prepending zeros can be decrypted by this vulnerability.
- If you don't use RSA PKCS1-v1_5 or RSA-OAEP decryption, this vulnerability is not affected.
- Risk to forge contents of encrypted message is very low.
- Risk to raise memory corruption is low since jsrsasign uses BigInteger class.
Patches
Users using RSA PKCS1-v1_5 or RSA-OAEP decryption should upgrade to 8.0.18.
Workarounds
Reject RSA PKCS1-v1_5 or RSA-OAEP encrypted message with unnecessary prepending zeros.
References
https://nvd.nist.gov/vuln/detail/CVE-2020-14967 https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2020-14967 https://vuldb.com/?id.157124 https://kjur.github.io/jsrsasign/api/symbols/KJUR.crypto.Cipher.html#.decrypt https://github.com/kjur/jsrsasign/issues/439
Affected software
Click a technology to see all vulnerabilities affecting it.
| Platform | Package | Vulnerable versions | Fixed in |
|---|---|---|---|
| npm package | jsrsasign | < 8.0.18 | 8.0.18 |
References
- https://github.com/kjur/jsrsasign/security/advisories/GHSA-xxxq-chmp-67g4
- https://nvd.nist.gov/vuln/detail/CVE-2020-14967
- https://github.com/kjur/jsrsasign/issues/439
- https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2020-14967
- https://github.com/kjur/jsrsasign
- https://github.com/kjur/jsrsasign/releases/tag/8.0.17
- https://github.com/kjur/jsrsasign/releases/tag/8.0.18
- https://kjur.github.io/jsrsasign
- https://kjur.github.io/jsrsasign/api/symbols/KJUR.crypto.Cipher.html#.decrypt
- https://security.netapp.com/advisory/ntap-20200724-0001
- https://vuldb.com/?id.157124
- https://www.npmjs.com/package/jsrsasign
- CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H- Weakness (CWE)
CWE-119- Platform
- npm
- Package
jsrsasign- Disclosed
- 26.06.2020
- Updated
- 11.10.2026 10:22
Sources and licenses
OSV / GitHub Advisory Database - GHSA-xxxq-chmp-67g4 - CC BY 4.0
Vulnerability history: jsrsasign
All published vulnerabilities of this package (npm package), newest first. Shows whether this is a one-off slip or a package that needs watching.
- Total entries
- 14
- First → latest
- 06.2020 03.2026
- Without a fix
- 0
- Exploited in attacks
- 0
Severity breakdown
- Critical 4
- High 7
- Medium 2
- Low 1
Disclosures per year
- 2020: 4
- 2021: 1
- 2022: 2
- 2023: 0
- 2024: 1
- 2025: 0
- 2026: 6
-
RSA PKCS#1 decryption vulnerability with prepending zeros in jsrsasign this entry
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