USN-8087-2: python-cryptography regression

Publication date

16 March 2026

Overview

USN-8087-1 introduced a regression in python-cryptography


Packages

Details

USN-8087-1 fixed a vulnerability in python-cryptography. The update caused
a regression when using ECC algorithms with certain software. This update
fixes the problem.

We apologize for the inconvenience.

Original advisory details:

It was discovered that python-cryptography incorrectly handled subgroup
validation for SECT curves. A remote attacker could use this issue to
perform a subgroup attack and possibly recover the least significant bits
of private keys.

USN-8087-1 fixed a vulnerability in python-cryptography. The update caused
a regression when using ECC algorithms with certain software. This update
fixes the problem.

We apologize for the inconvenience.

Original advisory details:

It was discovered that python-cryptography incorrectly handled subgroup
validation for SECT curves. A remote attacker could use this issue to
perform a subgroup attack and possibly recover the least significant bits
of private keys.

Update instructions

In general, a standard system update will make all the necessary changes.

Learn more about how to get the fixes.

The problem can be corrected by updating your system to the following package versions:

Ubuntu Release Package Version
25.10 questing python3-cryptography –  43.0.0-1ubuntu1.2
24.04 LTS noble python3-cryptography –  41.0.7-4ubuntu0.4
22.04 LTS jammy python3-cryptography –  3.4.8-1ubuntu2.4

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