CVE-2023-23931
Publication date 7 February 2023
Last updated 18 August 2025
Ubuntu priority
Description
cryptography is a package designed to expose cryptographic primitives and recipes to Python developers. In affected versions `Cipher.update_into` would accept Python objects which implement the buffer protocol, but provide only immutable buffers. This would allow immutable objects (such as `bytes`) to be mutated, thus violating fundamental rules of Python and resulting in corrupted output. This now correctly raises an exception. This issue has been present since `update_into` was originally introduced in cryptography 1.8.
Status
| Package | Ubuntu Release | Status |
|---|---|---|
| python-cryptography | 25.10 questing |
Not affected
|
| 25.04 plucky |
Not affected
|
|
| 24.04 LTS noble |
Not affected
|
|
| 22.04 LTS jammy |
Fixed 3.4.8-1ubuntu2.1
|
|
| 20.04 LTS focal |
Fixed 2.8-3ubuntu0.2
|
|
| 18.04 LTS bionic |
Vulnerable
|
|
| 16.04 LTS xenial |
Not affected
|
|
| 14.04 LTS trusty | Ignored end of standard support, was not-affected |
Notes
mdeslaur
Per the upstream advisory: "This is a soundness bug -- it allows programmers to misuse an API, it cannot be exploited by attacker controlled data alone."
seth-arnold
Debian's update was incomplete, see 2.6.1-3+deb10u4
ccdm94
as per the advisory, this vulnerability was introduced in version 1.8.
Severity score breakdown
| Parameter | Value |
|---|---|
| Base score |
4.8 · Medium
|
| Attack vector | Network |
| Attack complexity | High |
| Privileges required | None |
| User interaction | None |
| Scope | Unchanged |
| Confidentiality | None |
| Integrity impact | Low |
| Availability impact | Low |
| Vector | CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:L |
References
Related Ubuntu Security Notices (USN)
- USN-6539-1
- python-cryptography vulnerabilities
- 6 December 2023