{"id":"CVE-2026-74496","revision":"fff21f852aca4a2eba003ae2656994b5","records":[{"revision":"fff21f852aca4a2eba003ae2656994b5","observedAt":"2026-10-23T15:48:27.903+00:00","statement":{"source":"cve-program","id":"CVE-2026-74496","aliases":[],"title":"fou: Fix use-after-free in fou_create()","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nfou: Fix use-after-free in fou_create()\n\nfou_create() publishes struct fou through sk_user_data before adding the\nnew FOU port to the per-netns list.  If fou_add_to_port_list() fails,\nthe error path frees fou while it is still reachable through\nsk_user_data.  A concurrent receive can then dereference the freed\nobject in fou_from_sock().\n\nThis ordering issue was previously noted in the linked discussion.\n\nThe failure is reachable when local port 0 is requested.  Each socket\nbinds to a different ephemeral port, but fou_cfg_cmp() compares the\nrequested port 0 and reports -EALREADY once an entry already exists.\n\nRelease the tunnel socket before freeing fou so sk_user_data is cleared\nfirst, and defer reclamation with kfree_rcu() to protect concurrent RCU\nreaders.  This matches the lifetime handling in fou_release().","state":0,"publishedAt":"2026-08-15T12:27:23.854+00:00","modifiedAt":"2026-10-16T19:05:50.395+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/fou_core.c\"\n                    ],\n                    \"versions\": [\n                        {\n                            \"version\": \"23461551c00628c3f3fe9cf837bf53cf8f212b63\",\n                            \"lessThan\": \"0ee628a58d83e571f36ec9f07624d6845e420c50\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        },\n                        {\n                            \"version\": \"23461551c00628c3f3fe9cf837bf53cf8f212b63\",\n                            \"lessThan\": \"a6fca682cfa2041e31aa72cc397c4a1406eb7468\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        },\n                        {\n                            \"version\": \"23461551c00628c3f3fe9cf837bf53cf8f212b63\",\n                            \"lessThan\": \"b3f9c3e60aa25453774f899d25b5e61dd0bec1d5\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        },\n                        {\n                            \"version\": \"23461551c00628c3f3fe9cf837bf53cf8f212b63\",\n                            \"lessThan\": \"99f4d3120b244f92e5df787152041296a2860cb5\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        },\n                        {\n                            \"version\": \"23461551c00628c3f3fe9cf837bf53cf8f212b63\",\n                            \"lessThan\": \"58835985c035a8333742f829ad7e0889a082f9d3\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        },\n                        {\n                            \"version\": \"23461551c00628c3f3fe9cf837bf53cf8f212b63\",\n                            \"lessThan\": \"9042867d4701728f0c6527215b11471759904d8f\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        },\n                        {\n                            \"version\": \"23461551c00628c3f3fe9cf837bf53cf8f212b63\",\n                            \"lessThan\": \"a28d8903bfe76089ea4bbdbff9976965f9ef8107\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        },\n                        {\n                            \"version\": \"23461551c00628c3f3fe9cf837bf53cf8f212b63\",\n                            \"lessThan\": \"b14361aca6350ff7907b0e9903c7b94dc7d5d4a0\",\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/fou_core.c\"\n                    ],\n                    \"versions\": [\n                        {\n                            \"version\": \"3.18\",\n                            \"status\": \"affected\"\n                        },\n                        {\n                            \"version\": \"0\",\n                            \"lessThan\": \"3.18\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"5.10.271\",\n                            \"lessThanOrEqual\": \"5.10.*\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"5.15.222\",\n                            \"lessThanOrEqual\": \"5.15.*\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"6.1.189\",\n                            \"lessThanOrEqual\": \"6.1.*\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"6.6.158\",\n                            \"lessThanOrEqual\": \"6.6.*\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"6.12.111\",\n                            \"lessThanOrEqual\": \"6.12.*\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"6.18.53\",\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:U/C:H/I:H/A:H","score":7.8,"severity":"HIGH"}],"references":["https://git.kernel.org/stable/c/0ee628a58d83e571f36ec9f07624d6845e420c50","https://git.kernel.org/stable/c/a6fca682cfa2041e31aa72cc397c4a1406eb7468","https://git.kernel.org/stable/c/b3f9c3e60aa25453774f899d25b5e61dd0bec1d5","https://git.kernel.org/stable/c/99f4d3120b244f92e5df787152041296a2860cb5","https://git.kernel.org/stable/c/58835985c035a8333742f829ad7e0889a082f9d3","https://git.kernel.org/stable/c/9042867d4701728f0c6527215b11471759904d8f","https://git.kernel.org/stable/c/a28d8903bfe76089ea4bbdbff9976965f9ef8107","https://git.kernel.org/stable/c/b14361aca6350ff7907b0e9903c7b94dc7d5d4a0"],"sourceUrl":"https://www.cve.org/CVERecord?id=CVE-2026-74496","license":"CVE Program Terms of Use","key":"cve-program:CVE-2026-74496","identifiers":["CVE-2026-74496"]},"retained":false,"historicalAffected":[]}],"coverage":[]}