{"id":"CVE-2026-74562","revision":"9bfd71f8e71643b29126f5d8af84361f","records":[{"revision":"9bfd71f8e71643b29126f5d8af84361f","observedAt":"2026-10-23T15:48:27.903+00:00","statement":{"source":"cve-program","id":"CVE-2026-74562","aliases":[],"title":"nexthop: take nh->lock for f6i_list walks in replace check and notify","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nnexthop: take nh->lock for f6i_list walks in replace check and notify\n\nfib6_check_nh_list() and __nexthop_replace_notify() walk nh->f6i_list\nduring an RTNL-serialized nexthop replace without holding nh->lock. IPv6\nRTM_NEWROUTE/RTM_DELROUTE run without RTNL and mutate that list under\nnh->lock (fib6_add_rt2node_nh(), fib6_purge_rt()), so both walks race a\nconcurrent route delete that unlinks and frees a fib6_info:\n\n  BUG: KASAN: slab-use-after-free in rt6_fill_node.isra.0 (net/ipv6/route.c:5799)\n  Read of size 4 at addr ffff888014607e64 by task exploit/143\n   rt6_fill_node.isra.0 (net/ipv6/route.c:5799)\n   fib6_rt_update (net/ipv6/route.c:6412)\n   __nexthop_replace_notify (net/ipv4/nexthop.c:2542)\n   rtm_new_nexthop (net/ipv4/nexthop.c:2554)\n   rtnetlink_rcv_msg (net/core/rtnetlink.c:7076)\n\n  BUG: KASAN: slab-use-after-free in fib6_check_nh_list (net/ipv4/nexthop.c:1605)\n  Read of size 8 at addr ffff888014a7d068 by task exploit/142\n   fib6_check_nh_list (net/ipv4/nexthop.c:1605)\n   rtm_new_nexthop (net/ipv4/nexthop.c:2575)\n   rtnetlink_rcv_msg (net/core/rtnetlink.c:7076)\n\nBoth walks only read the entries and take no tb6_lock, so protect them\nwith nh->lock; fib6_rt_update() uses gfp_any(), which returns GFP_ATOMIC\nunder the lock.","state":0,"publishedAt":"2026-08-15T12:28:05.154+00:00","modifiedAt":"2026-10-15T10:09:16.149+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/ipv4/nexthop.c\"\n                    ],\n                    \"versions\": [\n                        {\n                            \"version\": \"081efd18326e353c6fbfdeff903a83edde953f72\",\n                            \"lessThan\": \"4b296d176580a85ccbc7135ebdf66c42087b23a2\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        },\n                        {\n                            \"version\": \"081efd18326e353c6fbfdeff903a83edde953f72\",\n                            \"lessThan\": \"bb2b072c619c1f741a6234257050f72005dc63ef\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        },\n                        {\n                            \"version\": \"081efd18326e353c6fbfdeff903a83edde953f72\",\n                            \"lessThan\": \"072cd1f21819dedd2252e704d255de3b0cfc61a7\",\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/ipv4/nexthop.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\": \"6.18.57\",\n                            \"lessThanOrEqual\": \"6.18.*\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"7.1.8\",\n                            \"lessThanOrEqual\": \"7.1.*\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"7.2\",\n                            \"lessThanOrEqual\": \"*\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"original_commit_for_fix\"\n                        }\n                    ]\n                }"}],"metrics":[{"system":"CVSS 3.1","vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H","score":8.8,"severity":"HIGH"}],"references":["https://git.kernel.org/stable/c/4b296d176580a85ccbc7135ebdf66c42087b23a2","https://git.kernel.org/stable/c/bb2b072c619c1f741a6234257050f72005dc63ef","https://git.kernel.org/stable/c/072cd1f21819dedd2252e704d255de3b0cfc61a7"],"sourceUrl":"https://www.cve.org/CVERecord?id=CVE-2026-74562","license":"CVE Program Terms of Use","key":"cve-program:CVE-2026-74562","identifiers":["CVE-2026-74562"]},"retained":false,"historicalAffected":[]}],"coverage":[]}