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Improper Input Validation Affecting python-cryptography package, versions <2.1.4-1ubuntu1.2

Severity

 Recommended
medium

Based on Ubuntu security rating.

Threat Intelligence

EPSS
0.18% (56th percentile)

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  • Snyk IDSNYK-UBUNTU1804-PYTHONCRYPTOGRAPHY-312007
  • published22 Jul 2018
  • disclosed30 Jul 2018
Report a new vulnerability Found a mistake?

Introduced: 22 Jul 2018

CVE-2018-10903  (opens in a new tab)
CWE-20  (opens in a new tab)

How to fix?

Upgrade Ubuntu:18.04 python-cryptography to version 2.1.4-1ubuntu1.2 or higher.

NVD Description

Note: Versions mentioned in the description apply only to the upstream python-cryptography package and not the python-cryptography package as distributed by Ubuntu. See How to fix? for Ubuntu:18.04 relevant fixed versions and status.

A flaw was found in python-cryptography versions between >=1.9.0 and <2.3. The finalize_with_tag API did not enforce a minimum tag length. If a user did not validate the input length prior to passing it to finalize_with_tag an attacker could craft an invalid payload with a shortened tag (e.g. 1 byte) such that they would have a 1 in 256 chance of passing the MAC check. GCM tag forgeries can cause key leakage.