FRRouting (FRR) versions stable/10.0 through stable/10.6 suffer from missing input validation in the MP_REACH_NLRI component. An authenticated attacker can send a specially crafted UPDATE message causing the FRR process to crash or become unresponsive, resulting in a denial of service. The flaw is a CWE‑20 improper input validation issue triggered by malformed routing protocol messages.

The affected system is FRRouting, commonly deployed on routers and routing platforms. Vulnerable releases include stable/10.0 up to stable/10.6. No CNA vendor or product name is listed, but the software is identified via the GitHub references.

The CVSS score is 6.5, indicating moderate severity, and the EPSS score is less than 1%, suggesting a low likelihood of exploitation. The vulnerability is not listed in the CISA KEV catalog. The attack requires the attacker to authenticate to the FRRouting instance or have access to a peer capable of injecting OSPF UPDATE messages. Based on the description, the attack vector is inferred to be network‑level, leveraging OSPF MP_REACH_NLRI messages sent from an authenticated or trusted peer.