USN-4233-2: GnuTLS update
23 January 2020
A security issue affects these releases of Ubuntu and its derivatives:
- Ubuntu 18.04 LTS
- Ubuntu 16.04 LTS
USN-4233-1 marked SHA1 as untrusted in GnuTLS with no workaround.
- gnutls28 - GNU TLS library
USN-4233-1 disabled SHA1 being used for digital signature operations in GnuTLS. In certain network environments, certificates using SHA1 may still be in use. This update adds the %VERIFY_ALLOW_BROKEN and %VERIFY_ALLOW_SIGN_WITH_SHA1 priority strings that can be used to temporarily re-enable SHA1 until certificates can be replaced with a stronger algorithm.
Original advisory details:
As a security improvement, this update marks SHA1 as being untrusted for digital signature operations.
The problem can be corrected by updating your system to the following package versions:
To update your system, please follow these instructions: https://wiki.ubuntu.com/Security/Upgrades.
In general, a standard system update will make all the necessary changes.