CVE-2026-99121
In the Linux kernel, the following vulnerability has been resolved: ipv4: avoid divide by zero in fib_rebalance fib_rebalance() computes the total eligible nexthop weight in one pass and programs upper bounds in a second pass. A concurrent change to ignore_routes_with_linkdown can make the first pass return zero while the second pass sees an eligible nexthop, resulting in division by zero. If the first pass reports a zero total, set each nexthop upper bound to -1 and skip the division. This matches the IPv6 fix in commit d2c26c2911dd ("ipv6: avoid divide by zero in rt6_multipath_rebalance") and preserves the lock-free rebalance path.
- Status
- Received - 416baaa9-dc9f-4396-8d5f-8c081fb06d67
- Published
- 2026-10-28
- Last modified
- 2026-10-28
Affected products
References
- https://git.kernel.org/stable/c/5dac5c7ba8f5f3fb4bf29f2a2c3cb552f5b83c8f
- https://git.kernel.org/stable/c/d5520e815c4b1427104ce1428ee23821f2aa824d
- https://git.kernel.org/stable/c/5046d2880fec7d49ebed2fd2866747ee1d06ad71
