HIGH7.5
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.
CVSS 2.0MEDIUM 5.0
CVSS:2.0/AV:N/AC:L/Au:N/C:P/I:N/A:NCVSS 3.xHIGH 7.5
CVSS:3.x/CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:NReferences
- https://access.redhat.com/errata/RHSA-2018:3600
- https://bugzilla.redhat.com/show_bug.cgi?id=CVE-2018-10903
- https://github.com/pyca/cryptography/pull/4342/commits/688e0f673bfbf43fa898994326c6877f00ab19ef
- https://usn.ubuntu.com/3720-1/
- https://access.redhat.com/errata/RHSA-2018:3600
- https://bugzilla.redhat.com/show_bug.cgi?id=CVE-2018-10903
- https://github.com/pyca/cryptography/pull/4342/commits/688e0f673bfbf43fa898994326c6877f00ab19ef
- https://usn.ubuntu.com/3720-1/