CVE-2026-97615

Summary

In the Linux kernel, the following vulnerability has been resolved:

net: bridge: use option bits for CFM/MRP frame handlers

CFM and MRP register a global br_frame_type whose hlist_node is linked into the per-bridge frame_type_list when the first MEP/MRP instance is created. Enabling the protocol on multiple bridges therefore inserts the same node into multiple lists. Unregistering it on one bridge then corrupts list state belonging to another.

These handlers can only be installed once per bridge, and they are uncommon. Track their per-bridge enable state with net_bridge option bits, which already live on the Rx hot cache line, and dispatch the matching handler directly from the receive path. Check both bits together first as an unlikely case.

Remove the generic frame_type_list and br_frame_type helpers, which have had no other users since CFM and MRP were added. That shrinks struct net_bridge by 8 bytes and drops the list walk from the fast path. When neither protocol is compiled in, BR_CFM_MRP_OPTS is 0 and the compiler prunes the branch.

Affected Software

VendorProductVersion RangeStatus
LinuxLinux90c628dd47ff4178f645b34938470bf43d02d123 < 994fd705ca498223d188024cde833739a9dddbd2affected
LinuxLinux90c628dd47ff4178f645b34938470bf43d02d123 < 42e033c8f30fd2923ccac3373ae70797e521dae1affected
LinuxLinux90c628dd47ff4178f645b34938470bf43d02d123 < 7a49e6b16f36b8e085521699adbca3e321b6dd0caffected
LinuxLinux5.11affected
LinuxLinux0 < 5.11unaffected
LinuxLinux6.18.53 <= 6.18.*unaffected
LinuxLinux7.2.7 <= 7.2.*unaffected
LinuxLinux7.3-rc3 <= *unaffected

Weaknesses

References