{"id":"CVE-2026-99121","published":"2026-10-28T11:17:31.733","lastModified":"2026-10-28T11:17:31.733","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nipv4: avoid divide by zero in fib_rebalance\n\nfib_rebalance() computes the total eligible nexthop weight in one pass\nand programs upper bounds in a second pass. A concurrent change to\nignore_routes_with_linkdown can make the first pass return zero while\nthe second pass sees an eligible nexthop, resulting in division by zero.\n\nIf the first pass reports a zero total, set each nexthop upper bound to\n-1 and skip the division. This matches the IPv6 fix in commit\nd2c26c2911dd (\"ipv6: avoid divide by zero in rt6_multipath_rebalance\")\nand preserves the lock-free rebalance path.","cvssScore":null,"cvssSeverity":null,"cvssVector":null,"cwes":[],"vendors":[],"products":[],"references":[{"url":"https://git.kernel.org/stable/c/5046d2880fec7d49ebed2fd2866747ee1d06ad71","tags":[]},{"url":"https://git.kernel.org/stable/c/5dac5c7ba8f5f3fb4bf29f2a2c3cb552f5b83c8f","tags":[]},{"url":"https://git.kernel.org/stable/c/d5520e815c4b1427104ce1428ee23821f2aa824d","tags":[]}],"exploitRefs":[],"hasPoc":false,"ai":null}