{"id":"CVE-2021-29443","aliases":["GHSA-58f5-hfqc-jgch"],"url":"https://o3.security/vulnerability/CVE-2021-29443","summary":"Padding Oracle Attack due to Observable Timing Discrepancy in jose","details":"jose is an npm library providing a number of cryptographic operations.\n### Impact\n\n[AES_CBC_HMAC_SHA2 Algorithm](https://tools.ietf.org/html/rfc7518#section-5.2) (A128CBC-HS256, A192CBC-HS384, A256CBC-HS512) decryption would always execute both HMAC tag verification and CBC decryption, if either failed `JWEDecryptionFailed` would be thrown. But a possibly observable difference in timing when padding error would occur while decrypting the ciphertext makes a padding oracle and an adversary might be able to make use of that oracle to decrypt data without knowing the decryption key by issuing on average 128*b calls to the padding oracle (where b is the number of bytes in the ciphertext block).\n\n### Patches\n\nAll major release versions have had a patch released which ensures the HMAC tag is verified before performing CBC decryption. The fixed versions are `^1.28.1 || ^2.0.5 || >=3.11.4`.\n\nUsers should upgrade their v1.x dependency to [`^1.28.1`](https://github.com/panva/jose/releases/tag/v1.28.1), their v2.x dependency to [`^2.0.5`](https://github.com/panva/jose/releases/tag/v2.0.5), and their v3.x dependency to [`^3.11.4`](https://github.com/panva/jose/releases/tag/v3.11.4)\n\n### Credits\nThanks to Morgan Brown of Microsoft for bringing this up and Eva Sarafianou (@esarafianou) for helping to score this advisory.","published":"2021-04-16T18:15:13.590Z","modified":"2026-07-09T14:06:14.174616Z","cvss":{"score":5.9,"severity":"MEDIUM","vector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N"},"epss":null,"cisaKev":null,"exploitsKnown":0,"affectedPackages":[{"ecosystem":"npm","name":"jose","fixedVersion":"1.28.1"},{"ecosystem":"npm","name":"jose","fixedVersion":"2.0.5"},{"ecosystem":"npm","name":"jose","fixedVersion":"3.11.4"}],"fix":null,"references":[{"type":"ADVISORY","url":"https://www.npmjs.com/package/jose"},{"type":"FIX","url":"https://github.com/panva/jose/security/advisories/GHSA-58f5-hfqc-jgch"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2021-29443"}],"provenance":{"sources":["OSV.dev","FIRST.org (EPSS)"],"lastVerified":"2026-07-09T14:06:14.174616Z"}}