{"cve":"CVE-2026-98276","nvd":{"published":"2026-10-06T09:18:17.360","modified":"2026-10-19T10:18:28.973","status":"Received","description":"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\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.","cvss_v4":null,"cvss_v3":{"version":"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},"cwes":[],"references":["https://git.kernel.org/stable/c/17b2a1eb97fdb2a2cbaeab3b146b26797ea9311f","https://git.kernel.org/stable/c/18899e2e4023369a8f7739c2255a59a9748d8d17","https://git.kernel.org/stable/c/1f73253add8365d0dad0a4f421acaa8c21d20cef","https://git.kernel.org/stable/c/3b12d3967e96f1b7b977d9fc352ae29a1b299a82","https://git.kernel.org/stable/c/88c804847dd87dc613b771b392ccecdb94725032"],"products":[],"source":"nvd","synced_at":"2026-10-19T22:57:46.668721662+00:00"},"epss":{"cve":"CVE-2026-98276","score":0.00126,"percentile":0.02237,"date":"2026-10-25"},"kev":null,"osv":[],"attribution":["This product uses the NVD API but is not endorsed or certified by the NVD.","EPSS scores: FIRST Exploit Prediction Scoring System, https://www.first.org/epss","Known exploited vulnerabilities: CISA Known Exploited Vulnerabilities Catalog, https://www.cisa.gov/known-exploited-vulnerabilities-catalog","Package advisories: OSV (https://osv.dev), from the GitHub Advisory Database, PyPA, Go, RustSec and other ecosystem databases, under CC-BY 4.0 or CC0","CVE records: the CVE Program's CVE List (https://www.cve.org), under its terms of use (https://www.cve.org/Legal/TermsOfUse). CVE is a registered trademark of The MITRE Corporation; this product is not affiliated with the CVE Program."]}