CVE-2026-31420

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

bridge: mrp: reject zero test interval to avoid OOM panic

br_mrp_start_test() and br_mrp_start_in_test() accept the user-supplied

interval value from netlink without validation. When interval is 0,

usecs_to_jiffies(0) yields 0, causing the delayed work

(br_mrp_test_work_expired / br_mrp_in_test_work_expired) to reschedule

itself with zero delay. This creates a tight loop on system_percpu_wq

that allocates and transmits MRP test frames at maximum rate, exhausting

all system memory and causing a kernel panic via OOM deadlock.

The same zero-interval issue applies to br_mrp_start_in_test_parse()

for interconnect test frames.

Use NLA_POLICY_MIN(NLA_U32, 1) in the nla_policy tables for both

IFLA_BRIDGE_MRP_START_TEST_INTERVAL and

IFLA_BRIDGE_MRP_START_IN_TEST_INTERVAL, so zero is rejected at the

netlink attribute parsing layer before the value ever reaches the

workqueue scheduling code. This is consistent with how other bridge

subsystems (br_fdb, br_mst) enforce range constraints on netlink

attributes.