{"id":"CVE-2026-74561","revision":"688d3914a6a34dfc9b66a31a07a12419","records":[{"revision":"688d3914a6a34dfc9b66a31a07a12419","observedAt":"2026-10-23T15:48:27.903+00:00","statement":{"source":"cve-program","id":"CVE-2026-74561","aliases":[],"title":"nexthop: avoid unlocked f6i_list walk in nh_rt_cache_flush","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nnexthop: avoid unlocked f6i_list walk in nh_rt_cache_flush\n\nnh_rt_cache_flush() walks nh->f6i_list during an RTNL-serialized nexthop\nreplace without holding nh->lock, racing the unlocked IPv6 route\nadd/delete that mutate the list under nh->lock and free fib6_info\nentries (nh_rt_cache_flush() is inlined into rtm_new_nexthop()):\n\n  BUG: KASAN: slab-use-after-free in nh_rt_cache_flush (net/ipv4/nexthop.c:2243)\n  Read of size 8 at addr ffff888012953e18 by task exploit/146\n   nh_rt_cache_flush (net/ipv4/nexthop.c:2243)\n   replace_nexthop (net/ipv4/nexthop.c:2610)\n   rtm_new_nexthop (net/ipv4/nexthop.c:3323)\n   rtnetlink_rcv_msg (net/core/rtnetlink.c:7076)\n\nUnlike the other f6i_list walks, this one bumps each route's sernum via\nfib6_update_sernum_upto_root(), which needs tb6_lock; taking nh->lock\naround it would invert the established tb6_lock -> nh->lock order and\ndeadlock. As the only purpose is to invalidate cached dsts, bump the\nIPv6 sernum for the whole netns with rt_genid_bump_ipv6() instead,\nmirroring the rt_cache_flush() already done for IPv4 just above.","state":0,"publishedAt":"2026-08-15T12:28:04.525+00:00","modifiedAt":"2026-10-15T10:09:15.073+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\": \"f97fae992155b11da516a509c855ff9d0868b107\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        },\n                        {\n                            \"version\": \"081efd18326e353c6fbfdeff903a83edde953f72\",\n                            \"lessThan\": \"44f53e4331a30fabc38a411fae7524341b618db3\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        },\n                        {\n                            \"version\": \"081efd18326e353c6fbfdeff903a83edde953f72\",\n                            \"lessThan\": \"4787a6d2629b4e8c0b6bacab1f75c1660eca44d9\",\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/f97fae992155b11da516a509c855ff9d0868b107","https://git.kernel.org/stable/c/44f53e4331a30fabc38a411fae7524341b618db3","https://git.kernel.org/stable/c/4787a6d2629b4e8c0b6bacab1f75c1660eca44d9"],"sourceUrl":"https://www.cve.org/CVERecord?id=CVE-2026-74561","license":"CVE Program Terms of Use","key":"cve-program:CVE-2026-74561","identifiers":["CVE-2026-74561"]},"retained":false,"historicalAffected":[]}],"coverage":[]}