The vulnerability exists in dhcpcd's IPv6 Neighbor Discovery Router Advertisement processing. A malformed IPv6 Router Advertisement with a zero-length Neighbor Discovery option bypasses initial validation and is stored for later reparsing without adequate checks. This leads to the parser entering an infinite loop, consuming excessive CPU resources and causing denial of service. The root cause is inconsistent validation during Router Advertisement processing. Upstream fixes include discarding malformed Router Advertisements immediately and validating all Neighbor Discovery options before storing packets. Red Hat Enterprise Linux 10 ships with affected versions of dhcpcd. Red Hat has released updated dhcpcd packages to fix this issue.

Successful exploitation allows an unauthenticated attacker on the same Layer-2 network segment to cause dhcpcd to enter an infinite loop, resulting in excessive CPU utilization and denial of service on affected systems. There is no impact on confidentiality or integrity, only availability is affected.

Red Hat has released updated dhcpcd packages that fix this vulnerability. Administrators should apply the security update (e.g., dhcpcd-10.0.6-11.el10_2) as soon as possible. Until the update is applied, mitigation includes disabling IPv6 Router Advertisement processing on interfaces where it is not required or restricting acceptance of untrusted ICMPv6 Router Advertisements using network filtering. Systems relying on IPv6 Stateless Address Autoconfiguration or Router Advertisement-based configuration should evaluate operational impact before applying these mitigations.