{"id":"CVE-2026-74496","title":"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","summary":"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_por…","severity":"high","cvss":7.8,"cvssVector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","vendor":"Linux","product":"Linux","affected":["Linux >= 23461551c00628c3f3fe9cf837bf53cf8f212b63 < 58835985c035a8333742f829ad7e0889a082f9d3","Linux >= 23461551c00628c3f3fe9cf837bf53cf8f212b63 < 9042867d4701728f0c6527215b11471759904d8f","Linux >= 23461551c00628c3f3fe9cf837bf53cf8f212b63 < a28d8903bfe76089ea4bbdbff9976965f9ef8107","Linux >= 23461551c00628c3f3fe9cf837bf53cf8f212b63 < b14361aca6350ff7907b0e9903c7b94dc7d5d4a0","Linux 3.18"],"published":"2026-08-15","updated":"2026-09-21","sourceUpdated":"2026-09-21T14:17:19.223","source":"NVD","sourceUrl":"https://nvd.nist.gov/vuln/detail/CVE-2026-74496","references":[{"url":"https://git.kernel.org/stable/c/58835985c035a8333742f829ad7e0889a082f9d3","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/9042867d4701728f0c6527215b11471759904d8f","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/a28d8903bfe76089ea4bbdbff9976965f9ef8107","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/b14361aca6350ff7907b0e9903c7b94dc7d5d4a0","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"}],"tags":["nvd","cve.org"],"epss":0.00125,"epssPercentile":0.02549,"ingestedAt":"2026-09-21T13:37:22.838Z","slug":"CVE-2026-74496","body":"## Overview\n\nIn 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().\n\n## Remediation\n\nRefer to the linked advisories for vendor-supplied fixes and affected version ranges.","depth":"twilight","depthScore":43,"depthScoreParts":{"impact":42.9,"likelihood":0,"exploitation":0,"ransomware":0},"changes":[]}