Ubuntu alert USN-8335-1 (pyopenssl)

From:
             
 
noreply+usn-bot@canonical.com
To:
             
 
ubuntu-security-announce@lists.ubuntu.com
Subject:
             
 
[USN-8335-1] pyOpenSSL vulnerability
Date:
             
 
Thu, 28 May 2026 14:15:39 +0000
Message-ID:
             
 
<E1wSbWN-0004bG-DR@lists.ubuntu.com>
==========================================================================
Ubuntu Security Notice USN-8335-1
May 28, 2026

pyopenssl 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:

pyOpenSSL could allow unintended access to network services.

Software Description:
- pyopenssl: Python wrapper around the OpenSSL library

Details:

It was discovered that pyOpenSSL incorrectly handled exceptions in the
tlsext_servername callback. This could result in connections being accepted
after an exception, contrary to expectations.

Update instructions:

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

Ubuntu 20.04 LTS
  python-openssl                  19.0.0-1ubuntu0.1~esm1
                                  Available with Ubuntu Pro
  python3-openssl                 19.0.0-1ubuntu0.1~esm1
                                  Available with Ubuntu Pro

Ubuntu 18.04 LTS
  python-openssl                  17.5.0-1ubuntu1+esm1
                                  Available with Ubuntu Pro
  python3-openssl                 17.5.0-1ubuntu1+esm1
                                  Available with Ubuntu Pro

Ubuntu 16.04 LTS
  python-openssl                  0.15.1-2ubuntu0.2+esm1
                                  Available with Ubuntu Pro
  python3-openssl                 0.15.1-2ubuntu0.2+esm1
                                  Available with Ubuntu Pro

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

References:
  https://ubuntu.com/security/notices/USN-8335-1
  CVE-2026-27448


Attachment: signature.asc (type=application/pgp-signature)
-----BEGIN PGP SIGNATURE-----
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=ZGnA
-----END PGP SIGNATURE-----