========================================================================== Ubuntu Security Notice USN-8087-3 April 28, 2026
python-cryptography vulnerability
==========================================================================
A security issue affects these releases of Ubuntu and its derivatives:
- Ubuntu 20.04 LTS
- Ubuntu 18.04 LTS
- Ubuntu 16.04 LTS
Summary:
python-cryptography could be made to expose sensitive information over the
network.
Software Description:
- python-cryptography: Cryptography Python library
Details:
USN-8087-1 fixed a vulnerability in python-cryptography. This update
provides the corresponding update to Ubuntu 16.04 LTS, Ubuntu 18.04 LTS,
and Ubuntu 20.04 LTS.
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:
The problem can be corrected by updating your system to the following
package versions:
Ubuntu 20.04 LTS
python-cryptography 2.8-3ubuntu0.3+esm2
Available with Ubuntu Pro
python3-cryptography 2.8-3ubuntu0.3+esm2
Available with Ubuntu Pro
Ubuntu 18.04 LTS
python-cryptography 2.1.4-1ubuntu1.4+esm3
Available with Ubuntu Pro
python3-cryptography 2.1.4-1ubuntu1.4+esm3
Available with Ubuntu Pro
Ubuntu 16.04 LTS
python-cryptography 1.2.3-1ubuntu0.3+esm3
Available with Ubuntu Pro
python3-cryptography 1.2.3-1ubuntu0.3+esm3
Available with Ubuntu Pro
In general, a standard system update will make all the necessary changes.
References:
https://ubuntu.com/security/notices/USN-8087-3
https://ubuntu.com/security/notices/USN-8087-2
https://ubuntu.com/security/notices/USN-8087-1
CVE-2026-26007
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