{"id":"CVE-2026-98276","title":"In the Linux kernel, the following vulnerability has been resolved:\n\nnet: lock the socket in sock_gettstamp()\n\nsk->sk_flags must only be changed while holding the socket lock,\nbecause sock_set_flag() and sock_reset_flag() use non atomic\n…","summary":"In the Linux kernel, the following vulnerability has been resolved:\n\nnet: lock the socket in sock_gettstamp()\n\nsk->sk_flags must only be changed while holding the socket lock,\nbecause sock_set_flag() and sock_reset_flag() use non atomic\n…","severity":"none","vendor":"Linux","product":"Linux","affected":["Linux >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 < 18899e2e4023369a8f7739c2255a59a9748d8d17","Linux >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 < 88c804847dd87dc613b771b392ccecdb94725032","Linux >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 < 3b12d3967e96f1b7b977d9fc352ae29a1b299a82","Linux >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 < 17b2a1eb97fdb2a2cbaeab3b146b26797ea9311f","Linux >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 < 1f73253add8365d0dad0a4f421acaa8c21d20cef","Linux >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 < d9f96bc2d822501f84d1caa6275a2c6b316ca2c4","Linux >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 < 899650bbf985b7bfd2a7b808357df9b16e6d6959","Linux >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 < 9ed55f3dbef4f4adfe65eb03b0c35c53229a8490","Linux 2.6.12"],"published":"2026-10-06","updated":"2026-10-06","sourceUpdated":"2026-10-06T09:18:17.360","source":"NVD","sourceUrl":"https://nvd.nist.gov/vuln/detail/CVE-2026-98276","references":[{"url":"https://git.kernel.org/stable/c/17b2a1eb97fdb2a2cbaeab3b146b26797ea9311f","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/18899e2e4023369a8f7739c2255a59a9748d8d17","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/1f73253add8365d0dad0a4f421acaa8c21d20cef","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/3b12d3967e96f1b7b977d9fc352ae29a1b299a82","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/88c804847dd87dc613b771b392ccecdb94725032","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/899650bbf985b7bfd2a7b808357df9b16e6d6959","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/9ed55f3dbef4f4adfe65eb03b0c35c53229a8490","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/d9f96bc2d822501f84d1caa6275a2c6b316ca2c4","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"}],"tags":["nvd","cve.org"],"ingestedAt":"2026-10-06T08:50:17.423Z","slug":"CVE-2026-98276","body":"## Overview\n\nIn the Linux kernel, the following vulnerability has been resolved:\n\nnet: lock the socket in sock_gettstamp()\n\nsk->sk_flags must only be changed while holding the socket lock,\nbecause sock_set_flag() and sock_reset_flag() use non atomic\noperations (__set_bit() and __clear_bit()).\n\nsock_gettstamp() is one of the last places where a bit of sk->sk_flags\nis changed from a syscall without owning the socket lock, through\nsock_enable_timestamp(sk, SOCK_TIMESTAMP).\n\nsk_set_memalloc() and sk_clear_memalloc() also change sk->sk_flags\nwithout the socket lock, but their callers (nbd, iscsi_tcp, nvme-tcp,\nsunrpc, wireguard) need a careful audit, this will be addressed in a\nseparate patch.\n\nJungwoo Lee and Wongi Lee reported an UDP socket use-after-free\ncaused by this bug: a SIOCGSTAMPNS_NEW ioctl racing with bind()\ncan cancel the SOCK_RCU_FREE bit that udp_lib_get_port() just set,\nbecause both threads perform a read-modify-write on the same word.\n\n  CPU 0 (bind)                        CPU 1 (SIOCGSTAMPNS_NEW)\n  --------------------------------    ----------------------------\n  read sk_flags = F                   read sk_flags = F\n  compute F | BIT(SOCK_RCU_FREE)      compute F | BIT(SOCK_TIMESTAMP)\n  store F | BIT(SOCK_RCU_FREE)\n  sk_add_node_rcu(sk, ...)\n                                      store F | BIT(SOCK_TIMESTAMP)\n\nAfter the lost update, SOCK_RCU_FREE is clear while the socket is\nvisible to lockless UDP receive lookups. sk_destruct() then frees\nthe socket immediately instead of waiting for a RCU grace period,\nwhile the receive path still holds a reference-less pointer to it:\n\n BUG: KASAN: slab-use-after-free in ipv4_pktinfo_prepare+0x30/0x410\n Read of size 8 at addr ffff888008806610 by task exploit/207\n CPU: 0 UID: 1000 PID: 207 Comm: exploit Not tainted 6.12.95+ #1\n  ipv4_pktinfo_prepare+0x30/0x410\n  udp_queue_rcv_one_skb+0x51c/0x1180\n  udp_unicast_rcv_skb+0x109/0x350\n  ip_protocol_deliver_rcu+0x14b/0x310\n  ip_local_deliver_finish+0x29d/0x390\n  ip_local_deliver+0x24d/0x2a0\n\nOnly grab the socket lock when SOCK_TIMESTAMP has to be set,\nto keep the common case lockless.\n\n## Remediation\n\nRefer to the linked advisories for vendor-supplied fixes and affected version ranges.","depth":"sunlit","depthScore":3,"depthScoreParts":{"impact":2.8,"likelihood":0,"exploitation":0,"ransomware":0},"changes":[]}