Access Restriction Bypass The advisory has been revoked - it doesn't affect any version of package pyjwt (opens in a new tab)
Threat Intelligence
The probability is the direct output of the EPSS model, and conveys an overall sense of the threat of exploitation in the wild. The percentile measures the EPSS probability relative to all known EPSS scores. Note: This data is updated daily, relying on the latest available EPSS model version. Check out the EPSS documentation for more details.
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Start learning- Snyk IDSNYK-PYTHON-PYJWT-40753
- published4 Dec 2017
- disclosed22 Jun 2017
- creditUnknown
Introduced: 22 Jun 2017
CVE-2017-11424 (opens in a new tab)How to fix?
Upgrade pyjwt to version 1.5.1 or higher.
Overview
Affected versions of pyjwt are vulnerable to Access Restriction Bypass.
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.