Linux Kernel Local FDB Entry Manipulation Risk

CVE-2026-46086

What is CVE-2026-46086?

The Linux kernel exhibits a vulnerability related to local FDB entries where updates could lead to inconsistent values being observed by RCU readers. When fdb_delete_local() is invoked to modify an entry's destination (f->dst), it can cause readers to see an outdated or NULL value. This inconsistency can lead to a null pointer dereference, resulting in potential disruption of network services. The vulnerability has been addressed by implementing a stable snapshot mechanism in RCU readers ensuring that all checks and accesses utilize a consistent view of the data.

References