{"api_version":"1","generated_at":"2026-08-16T06:01:01+00:00","cve":"CVE-2026-74496","urls":{"html":"https://cve.report/CVE-2026-74496","api":"https://cve.report/api/cve/CVE-2026-74496.json","docs":"https://cve.report/api","cve_org":"https://www.cve.org/CVERecord?id=CVE-2026-74496","nvd":"https://nvd.nist.gov/vuln/detail/CVE-2026-74496"},"summary":{"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":"PUBLISHED","assigner":"Linux","published_at":"2026-08-15 13:17:54","updated_at":"2026-08-15 13:17:54"},"problem_types":[],"metrics":[],"references":[{"url":"https://git.kernel.org/stable/c/a28d8903bfe76089ea4bbdbff9976965f9ef8107","name":"https://git.kernel.org/stable/c/a28d8903bfe76089ea4bbdbff9976965f9ef8107","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/b14361aca6350ff7907b0e9903c7b94dc7d5d4a0","name":"https://git.kernel.org/stable/c/b14361aca6350ff7907b0e9903c7b94dc7d5d4a0","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://www.cve.org/CVERecord?id=CVE-2026-74496","name":"CVE Program record","refsource":"CVE.ORG","tags":["canonical"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-74496","name":"NVD vulnerability detail","refsource":"NVD","tags":["canonical","analysis"]}],"affected":[{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 23461551c00628c3f3fe9cf837bf53cf8f212b63 a28d8903bfe76089ea4bbdbff9976965f9ef8107 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 23461551c00628c3f3fe9cf837bf53cf8f212b63 b14361aca6350ff7907b0e9903c7b94dc7d5d4a0 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 3.18","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 3.18 semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 7.1.8 7.1.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 7.2-rc6 * original_commit_for_fix","platforms":[]}],"timeline":[],"solutions":[],"workarounds":[],"exploits":[],"credits":[],"nvd_cpes":[],"vendor_comments":[],"enrichments":{"kev":null,"epss":null,"legacy_qids":[]},"source_records":{"cve_program":{"containers":{"cna":{"affected":[{"defaultStatus":"unaffected","product":"Linux","programFiles":["net/ipv4/fou_core.c"],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","vendor":"Linux","versions":[{"lessThan":"a28d8903bfe76089ea4bbdbff9976965f9ef8107","status":"affected","version":"23461551c00628c3f3fe9cf837bf53cf8f212b63","versionType":"git"},{"lessThan":"b14361aca6350ff7907b0e9903c7b94dc7d5d4a0","status":"affected","version":"23461551c00628c3f3fe9cf837bf53cf8f212b63","versionType":"git"}]},{"defaultStatus":"affected","product":"Linux","programFiles":["net/ipv4/fou_core.c"],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","vendor":"Linux","versions":[{"status":"affected","version":"3.18"},{"lessThan":"3.18","status":"unaffected","version":"0","versionType":"semver"},{"lessThanOrEqual":"7.1.*","status":"unaffected","version":"7.1.8","versionType":"semver"},{"lessThanOrEqual":"*","status":"unaffected","version":"7.2-rc6","versionType":"original_commit_for_fix"}]}],"cpeApplicability":[{"nodes":[{"cpeMatch":[{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"7.1.8","versionStartIncluding":"3.18","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"7.2-rc6","versionStartIncluding":"3.18","vulnerable":true}],"negate":false,"operator":"OR"}]}],"descriptions":[{"lang":"en","value":"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()."}],"providerMetadata":{"dateUpdated":"2026-08-15T12:27:23.854Z","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","shortName":"Linux"},"references":[{"url":"https://git.kernel.org/stable/c/a28d8903bfe76089ea4bbdbff9976965f9ef8107"},{"url":"https://git.kernel.org/stable/c/b14361aca6350ff7907b0e9903c7b94dc7d5d4a0"}],"title":"fou: Fix use-after-free in fou_create()","x_generator":{"engine":"bippy-1.2.0"}}},"cveMetadata":{"assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","assignerShortName":"Linux","cveId":"CVE-2026-74496","datePublished":"2026-08-15T12:27:23.854Z","dateReserved":"2026-08-15T05:44:03.906Z","dateUpdated":"2026-08-15T12:27:23.854Z","state":"PUBLISHED"},"dataType":"CVE_RECORD","dataVersion":"5.2"},"nvd":{"publishedDate":"2026-08-15 13:17:54","lastModifiedDate":"2026-08-15 13:17:54","problem_types":[],"metrics":[],"configurations":[]},"legacy_mitre":{"record":{"CveYear":"2026","CveId":"74496","Ordinal":"1","Title":"fou: Fix use-after-free in fou_create()","CVE":"CVE-2026-74496","Year":"2026"},"notes":[{"CveYear":"2026","CveId":"74496","Ordinal":"1","NoteData":"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().","Type":"Description","Title":"fou: Fix use-after-free in fou_create()"}]}}}