GHSA-xxxq-chmp-67g4 RSA PKCS#1 decryption vulnerability with prepending zeros in jsrsasign

• npm jsrsasign: < 8.0.18 → fixed in 8.0.18

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