jpadilla/pyjwt · Security
PyJWT vulnerable to key confusion attacks
- GHSA ID
- GHSA-r9jw-mwhq-wp62
- CVE ID
- CVE-2017-11424
- Severity
- high
- Published
- Updated
- CVSS
- 7.5 · CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N
- CVSS v3
- 7.5 · CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N
Description
In PyJWT 1.5.0 and below the invalid_strings check in HMACAlgorithm.prepare_key does not account for all PEM encoded public keys. Specifically, the PKCS1 PEM encoded format would be allowed because it is prefaced with the string -----BEGIN RSA PUBLIC KEY----- which is not accounted for. This enables symmetric/asymmetric key confusion attacks against users using the PKCS1 PEM encoded public keys, which would allow an attacker to craft JWTs from scratch.