{"id":"CVE-2021-30246","aliases":["GHSA-27fj-mc8w-j9wg"],"url":"https://o3.security/vulnerability/CVE-2021-30246","summary":"RSA signature validation vulnerability on maleable encoded message in jsrsasign","details":"### Impact\nVulnerable jsrsasign will accept RSA signature with improper PKCS#1.5 padding.\nDecoded RSA signature value consists following form:\n`01(ff...(8 or more ffs)...ff)00[ASN.1 OF DigestInfo]`\nIts byte length must be the same as RSA key length, however such checking was not sufficient.\n\nTo make crafted message for practical attack is very hard.\n\n### Patches\nUsers validating RSA signature should upgrade to 10.2.0 or later.\n\n### Workarounds\nThere is no workaround. Not to use RSA signature validation in jsrsasign.\n\n### ACKNOWLEDGEMENT\nThanks to Daniel Yahyazadeh @yahyazadeh for reporting and analyzing this vulnerability.","published":"2021-04-07T21:15:16.153Z","modified":"2026-07-08T21:26:43.893729Z","cvss":{"score":9.1,"severity":"CRITICAL","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N"},"epss":null,"cisaKev":null,"exploitsKnown":null,"affectedPackages":[{"ecosystem":"npm","name":"jsrsasign","fixedVersion":"10.2.0"}],"fix":null,"references":[{"type":"ADVISORY","url":"https://github.com/kjur/jsrsasign/issues/478"},{"type":"ADVISORY","url":"https://github.com/kjur/jsrsasign/releases/tag/10.1.13"},{"type":"ADVISORY","url":"https://kjur.github.io/jsrsasign/"},{"type":"WEB","url":"https://github.com/kjur/jsrsasign/security/advisories/GHSA-27fj-mc8w-j9wg"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2021-30246"},{"type":"WEB","url":"https://kjur.github.io/jsrsasign"}],"provenance":{"sources":["OSV.dev","FIRST.org (EPSS)"],"lastVerified":"2026-07-08T21:26:43.893729Z"}}