Bug 2526703

Disclaimer: Community trackers are created by Red Hat Product Security team on a best effort basis. Package maintainers are required to ascertain if the flaw indeed affects their package, before starting the update process.

An out-of-bounds read was found in the DHCPv4 packet capture code of wicked. ni_capture_inspect_udp_header() in src/capture.c reports the IP total length as the payload length instead of the length of the remaining UDP payload. Consequently, the DHCP option walker in the DHCPv4 client (wickedd-dhcp4) reads up to ihl + 8 bytes — at most 68 bytes — past the end of the 1500-byte packet receive buffer. An unauthenticated attacker on the same network who sends a crafted DHCP/UDP packet can make the client parse adjacent heap memory as DHCP options, so that heap contents such as allocator metadata or pointer values can be interpreted into lease fields. The over-read is bounded to 68 bytes; no memory write, no attacker control over the adjacent bytes and no remote exfiltration primitive has been demonstrated. This issue affects wicked up to and including version 0.6.80.