A use-after-free vulnerability was found in systemd, a system and service manager. This issue occurs due to the on_stream_io() function and dns_stream_complete() function in ‘resolved-dns-stream.c’ not incrementing the reference counting for the DnsStream object. Therefore, other functions and callbacks called can dereference the DNSStream object, causing the use-after-free when the reference is still used later.
For Debian 9 stretch, these problems have been fixed in version 232-25+deb9u15.
We recommend that you upgrade your systemd packages.
Further information about Extended LTS security advisories can be found in the dedicated section of our website.