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Ubuntu: USN-3407-1 (CVE-2017-11424): PyJWT vulnerability

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Ubuntu: USN-3407-1 (CVE-2017-11424): PyJWT vulnerability

Severity
5
CVSS
(AV:N/AC:L/Au:N/C:N/I:P/A:N)
Published
08/24/2017
Created
07/25/2018
Added
08/31/2017
Modified
03/02/2020

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.

Solution(s)

  • ubuntu-upgrade-python-jwt
  • ubuntu-upgrade-python3-jwt

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