CVE-2018-10903

HIGH

python-cryptography 1.9.0-2.2 - GCM Tag Forgery via Insufficient Tag Length Validation

Title source: llm
STIX 2.1

Description

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 (4)

Core 4
Core References
Vendor Advisory vendor-advisory x_refsource_redhat
https://access.redhat.com/errata/RHSA-2018:3600
Third Party Advisory vendor-advisory x_refsource_ubuntu
https://usn.ubuntu.com/3720-1/
Issue Tracking, Patch, Third Party Advisory x_refsource_confirm
https://bugzilla.redhat.com/show_bug.cgi?id=CVE-2018-10903

Scores

CVSS v3 7.5
EPSS 0.0024
EPSS Percentile 47.0%
Attack Vector NETWORK
CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N

Details

CWE
CWE-20
Status published
Products (4)
canonical/ubuntu_linux 18.04
cryptography/python-cryptography 1.9.0 - 2.3
pypi/cryptography 1.9.0 - 2.3PyPI
redhat/openstack 13
Published Jul 30, 2018
Tracked Since Feb 18, 2026