Improper Input Validation Affecting python-cryptography package, versions <2.1.4-1ubuntu1.2
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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Test your applications- Snyk IDSNYK-UBUNTU1804-PYTHONCRYPTOGRAPHY-312007
- published22 Jul 2018
- disclosed30 Jul 2018
Introduced: 22 Jul 2018
CVE-2018-10903 (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.
References
- http://people.ubuntu.com/~ubuntu-security/cve/CVE-2018-10903
- https://security-tracker.debian.org/tracker/CVE-2018-10903
- https://github.com/pyca/cryptography/pull/4342/commits/688e0f673bfbf43fa898994326c6877f00ab19ef
- https://bugzilla.redhat.com/show_bug.cgi?id=CVE-2018-10903
- https://access.redhat.com/errata/RHSA-2018:3600
- https://usn.ubuntu.com/3720-1/