The Linux kernel vulnerability CVE-2026-80980 affected the net/smc connection state flags 'killed', 'freed', and 'out_of_sync', which were implemented as single-bit bitfields sharing one byte in struct smc_connection. Because these flags shared a byte and were updated without a common lock, concurrent writes could cause race conditions or inconsistent state. The fix involved separating each flag into its own byte, eliminating the read-modify-write conflicts. This change increased the struct size by two bytes and maintained boolean reads unchanged.

The vulnerability could lead to inconsistent or corrupted connection state in the net/smc subsystem due to concurrent unsynchronized writes to shared bits. This may affect the reliability or correctness of the affected kernel networking functionality. No specific exploit or active attacks are reported.

A fix has been implemented by modifying the struct smc_connection to allocate each state flag its own byte, preventing concurrent write conflicts. Users should apply the updated Linux kernel version containing this fix once available. No additional mitigations are indicated.