CVE-2018-10903
Published: 20 July 2018
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.
Notes
| Author | Note |
|---|---|
| leosilva | following what debian says, our xenial version is not affected. |
Priority
Status
| Package | Release | Status |
|---|---|---|
|
python-cryptography Launchpad, Ubuntu, Debian |
artful |
Ignored
(end of life)
|
| bionic |
Released
(2.1.4-1ubuntu1.2)
|
|
| trusty |
Does not exist
|
|
| upstream |
Needs triage
|
|
| xenial |
Not vulnerable
(code not present)
|
|
|
Patches: upstream: https://github.com/pyca/cryptography/pull/4342/commits/688e0f673bfbf43fa898994326c6877f00ab19ef |
||
Severity score breakdown
| Parameter | Value |
|---|---|
| Base score | 7.5 |
| Attack vector | Network |
| Attack complexity | Low |
| Privileges required | None |
| User interaction | None |
| Scope | Unchanged |
| Confidentiality | High |
| Integrity impact | None |
| Availability impact | None |
| Vector | CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N |