{
  "id": "CVE-2026-98276",
  "url": "https://spydr.io/cve/CVE-2026-98276",
  "published": "2026-10-06T09:18:17.360Z",
  "modified": "2026-10-06T09:18:17.360Z",
  "score": null,
  "severity": null,
  "cvss_version": null,
  "vector": null,
  "score_source": null,
  "epss": 0.00184,
  "epss_percentile": 0.07304,
  "exploited": false,
  "kev": null,
  "ssvc_exploitation": null,
  "vendors": [
    "Linux"
  ],
  "products": [
    "Linux"
  ],
  "cwes": [],
  "description": "In the Linux kernel, the following vulnerability has been resolved: net: lock the socket in sock_gettstamp() sk->sk_flags must only be changed while holding the socket lock, because sock_set_flag() and sock_reset_flag() use non atomic operations (__set_bit() and __clear_bit()). sock_gettstamp() is one of the last places where a bit of sk->sk_flags is changed from a syscall without owning the socket lock, through sock_enable_timestamp(sk, SOCK_TIMESTAMP). sk_set_memalloc() and sk_clear_memalloc() also change sk->sk_flags without the socket lock, but their callers (nbd, iscsi_tcp, nvme-tcp, sunrpc, wireguard) need a careful audit, this will be addressed in a separate patch. Jungwoo Lee and Wongi Lee reported an UDP socket use-after-free caused by this bug: a SIOCGSTAMPNS_NEW ioctl racing with bind() can cancel the SOCK_RCU_FREE bit that udp_lib_get_port() just set, because both threads perform a read-modify-write on the same word. CPU 0 (bind) CPU 1 (SIOCGSTAMPNS_NEW) -------------------------------- ---------------------------- read sk_flags = F read sk_flags = F compute F | BIT(SOCK_RCU_FREE) compute F | BIT(SOCK_TIMESTAMP) store F | BIT(SOCK_RCU_FREE) sk_add_node_rcu(sk, ...) store F | BIT(SOCK_TIMESTAMP) After the lost update, SOCK_RCU_FREE is clear while the socket is visible to lockless UDP receive lookups. sk_destruct() then frees the socket immediately instead of waiting for a RCU grace period, while the receive path still holds a reference-less pointer to it: BUG: KASAN: slab-use-after-free in ipv4_pktinfo_prepare+0x30/0x410 Read of size 8 at addr ffff888008806610 by task exploit/207 CPU: 0 UID: 1000 PID: 207 Comm: exploit Not tainted 6.12.95+ #1 ipv4_pktinfo_prepare+0x30/0x410 udp_queue_rcv_one_skb+0x51c/0x1180 udp_unicast_rcv_skb+0x109/0x350 ip_protocol_deliver_rcu+0x14b/0x310 ip_local_deliver_finish+0x29d/0x390 ip_local_deliver+0x24d/0x2a0 Only grab the socket lock when SOCK_TIMESTAMP has to be set, to keep the common case lockless.",
  "status": "Received",
  "score_type": null,
  "scores": {
    "cvss_v40": null,
    "cvss_v31": null,
    "cvss_v30": null
  },
  "references": [
    {
      "url": "https://git.kernel.org/stable/c/17b2a1eb97fdb2a2cbaeab3b146b26797ea9311f",
      "tags": []
    },
    {
      "url": "https://git.kernel.org/stable/c/18899e2e4023369a8f7739c2255a59a9748d8d17",
      "tags": []
    },
    {
      "url": "https://git.kernel.org/stable/c/1f73253add8365d0dad0a4f421acaa8c21d20cef",
      "tags": []
    },
    {
      "url": "https://git.kernel.org/stable/c/3b12d3967e96f1b7b977d9fc352ae29a1b299a82",
      "tags": []
    },
    {
      "url": "https://git.kernel.org/stable/c/88c804847dd87dc613b771b392ccecdb94725032",
      "tags": []
    },
    {
      "url": "https://git.kernel.org/stable/c/899650bbf985b7bfd2a7b808357df9b16e6d6959",
      "tags": []
    },
    {
      "url": "https://git.kernel.org/stable/c/9ed55f3dbef4f4adfe65eb03b0c35c53229a8490",
      "tags": []
    },
    {
      "url": "https://git.kernel.org/stable/c/d9f96bc2d822501f84d1caa6275a2c6b316ca2c4",
      "tags": []
    }
  ],
  "nvd_url": "https://nvd.nist.gov/vuln/detail/CVE-2026-98276",
  "covered_in": [],
  "attribution": [
    {
      "source": "NVD",
      "url": "https://nvd.nist.gov",
      "notice": "This product uses data from the NVD API but is not endorsed or certified by the NVD."
    },
    {
      "source": "CISA KEV",
      "url": "https://www.cisa.gov/known-exploited-vulnerabilities-catalog",
      "notice": "Known exploited vulnerabilities from the CISA KEV catalog."
    },
    {
      "source": "FIRST EPSS",
      "url": "https://www.first.org/epss",
      "notice": "Exploit prediction scores from FIRST EPSS."
    }
  ]
}