{"id":"CVE-2026-89790","revision":"b0aa07cdd31148a7b21691f5424704d4","records":[{"revision":"b0aa07cdd31148a7b21691f5424704d4","observedAt":"2026-10-23T15:48:27.903+00:00","statement":{"source":"cve-program","id":"CVE-2026-89790","aliases":[],"title":"ipv6: avoid divide by zero in rt6_multipath_rebalance","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nipv6: avoid divide by zero in rt6_multipath_rebalance\n\nrt6_multipath_rebalance() calculates the total eligible nexthop weight\nin one pass and programs upper bounds in a second pass. Since\nRTM_NEWROUTE is RTNL-free, a concurrent\nignore_routes_with_linkdown update can make the first pass return zero\nwhile the second sees an eligible nexthop, causing\nrt6_upper_bound_set() to divide by zero.\n\nUBSAN: division-overflow in net/ipv6/route.c:4845:17\nOops: divide error: 0000 [#1] SMP KASAN NOPTI\n  rt6_upper_bound_set() net/ipv6/route.c:4845\n  rt6_multipath_rebalance()\n  fib6_add_rt2node()\n  ip6_route_multipath_add()\n  inet6_rtm_newroute()\n\nSkip upper-bound calculation when the first pass reports a zero total.\nThis respects the lock-free performance considerations here and solves\ninsecure scenarios.","state":0,"publishedAt":"2026-09-16T08:48:26.343+00:00","modifiedAt":"2026-10-19T08:52:44.129+00:00","affected":[{"ecosystem":"Vendor product","name":"Linux","ranges":[],"versions":[],"rawVersionEvidence":"{\n                    \"product\": \"Linux\",\n                    \"vendor\": \"Linux\",\n                    \"defaultStatus\": \"unaffected\",\n                    \"repo\": \"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git\",\n                    \"programFiles\": [\n                        \"net/ipv6/route.c\"\n                    ],\n                    \"versions\": [\n                        {\n                            \"version\": \"bd11ff421d36abdb585b9104fa70057bf01b3110\",\n                            \"lessThan\": \"f30cf8fd9872299c0c27f9916252ba2b9f422dce\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        },\n                        {\n                            \"version\": \"bd11ff421d36abdb585b9104fa70057bf01b3110\",\n                            \"lessThan\": \"f82b5dbb2fef65b52a62d5ffe05e0483c4385a83\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        },\n                        {\n                            \"version\": \"bd11ff421d36abdb585b9104fa70057bf01b3110\",\n                            \"lessThan\": \"d2c26c2911dd1a363c488add4fb63eb5f0f28f87\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        }\n                    ]\n                }"},{"ecosystem":"Vendor product","name":"Linux","ranges":[],"versions":[],"rawVersionEvidence":"{\n                    \"product\": \"Linux\",\n                    \"vendor\": \"Linux\",\n                    \"defaultStatus\": \"affected\",\n                    \"repo\": \"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git\",\n                    \"programFiles\": [\n                        \"net/ipv6/route.c\"\n                    ],\n                    \"versions\": [\n                        {\n                            \"version\": \"6.16\",\n                            \"status\": \"affected\"\n                        },\n                        {\n                            \"version\": \"0\",\n                            \"lessThan\": \"6.16\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"6.18.52\",\n                            \"lessThanOrEqual\": \"6.18.*\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"7.2.6\",\n                            \"lessThanOrEqual\": \"7.2.*\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"7.3\",\n                            \"lessThanOrEqual\": \"*\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"original_commit_for_fix\"\n                        }\n                    ]\n                }"}],"metrics":[],"references":["https://git.kernel.org/stable/c/f30cf8fd9872299c0c27f9916252ba2b9f422dce","https://git.kernel.org/stable/c/f82b5dbb2fef65b52a62d5ffe05e0483c4385a83","https://git.kernel.org/stable/c/d2c26c2911dd1a363c488add4fb63eb5f0f28f87"],"sourceUrl":"https://www.cve.org/CVERecord?id=CVE-2026-89790","license":"CVE Program Terms of Use","key":"cve-program:CVE-2026-89790","identifiers":["CVE-2026-89790"]},"retained":false,"historicalAffected":[]}],"coverage":[]}