UBUNTU-CVE-2026-123036: Medium severity ubuntu/ansible vulnerability

A flaw was found in ansible-core. When a task marked nolog: true fails, the task result is censored before being emitted, but the exception field is retained because it is present in the PRESERVE allow-list in lib/ansible/internal/task.py, and the default stdout callback prints it through CallbackBase.handleexception. As a result, sensitive values the operator explicitly asked to hide can be disclosed: module argument-validation errors echo the argument value, templating errors print an Origin source snippet (the failing line plus the two preceding lines of the variables file, exposing neighbouring secrets from an -e @secrets.yml file), and fail/assert messages are printed in full. Secret material supplied as extra variables or variables files can therefore leak to terminal output, CI logs, and the stdout logs of any automation wrapping ansible-playbook, even though every task touching the secrets is marked nolog: true. This is a regression introduced with the ansible-core 2.19 data-tagging/templating rework; the behaviour does not occur on 2.16, where the error text is correctly censored.