CVE-2018-10903
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.
Does this matter?
High impact if exploited, but EPSS currently rates exploitation as unlikely (3.20%). Schedule it in the normal patch cycle and watch for a rise in EPSS or a public exploit.
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.
- CVSS 3.0
- 7.5 HIGHCVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
- EPSS
- 3.20% probability · 87th percentile
- CISA KEV
- Not listed
- Weakness
- CWE-20
- Affected
- cryptography/python-cryptography · redhat/openstack · canonical/ubuntu linux
- Source
- secalert@redhat.com
References
- https://access.redhat.com/errata/RHSA-2018:3600
- https://bugzilla.redhat.com/show_bug.cgi?id=CVE-2018-10903Issue Tracking, Patch, Third Party Advisory
- https://github.com/pyca/cryptography/pull/4342/commits/688e0f673bfbf43fa898994326c6877f00ab19efPatch, Third Party Advisory
- https://usn.ubuntu.com/3720-1/Third Party Advisory
- https://access.redhat.com/errata/RHSA-2018:3600
- https://bugzilla.redhat.com/show_bug.cgi?id=CVE-2018-10903Issue Tracking, Patch, Third Party Advisory
- https://github.com/pyca/cryptography/pull/4342/commits/688e0f673bfbf43fa898994326c6877f00ab19efPatch, Third Party Advisory
- https://usn.ubuntu.com/3720-1/Third Party Advisory
Source: NVD record, EPSS from FIRST.org, KEV from CISA. Refreshed daily.