Description
In systemd through 233, certain sizes passed to dns_packet_new in
systemd-resolved can cause it to allocate a buffer that's too small. A
malicious DNS server can exploit this via a response with a specially
crafted TCP payload to trick systemd-resolved into allocating a buffer
that's too small, and subsequently write arbitrary data beyond the end of
it.
Notes
chrisccoulson> I believe this was introduced in v223 by
https://github.com/systemd/systemd/commit/a0166609f782da91710dea9183d1bf138538db37
chrisccoulson> systemd-resolved is not used by default in Xenial. It is
spawned if a user execs the systemd-resolve utility, but that shouldn't
impact the system.