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.
Advisories
Source ID Title
Debian DSA Debian DSA DSA-3979-1 pyjwt security update
EUVD EUVD EUVD-2017-0103 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.
Github GHSA Github GHSA GHSA-r9jw-mwhq-wp62 PyJWT vulnerable to key confusion attacks
Ubuntu USN Ubuntu USN USN-3407-1 PyJWT vulnerability
Fixes

Solution

No solution given by the vendor.


Workaround

No workaround given by the vendor.

History

No history.

cve-icon MITRE

Status: PUBLISHED

Assigner: duo

Published:

Updated: 2024-08-05T18:12:39.550Z

Reserved: 2017-07-18T00:00:00

Link: CVE-2017-11424

cve-icon Vulnrichment

No data.

cve-icon NVD

Status : Deferred

Published: 2017-08-24T16:29:00.197

Modified: 2025-04-20T01:37:25.860

Link: CVE-2017-11424

cve-icon Redhat

Severity : Moderate

Publid Date: 2017-06-22T00:00:00Z

Links: CVE-2017-11424 - Bugzilla

cve-icon OpenCVE Enrichment

No data.