{
  "affected": [
    {
      "ranges": [
        {
          "events": [
            {
              "introduced": "2b06cdf3e688b98fcc9945873b5d42792bd4eee0"
            },
            {
              "fixed": "96b678d08268b5f5c6fc99d4289d9b7e334fc683"
            },
            {
              "fixed": "c283e9ada7fcb7dd4b10592623086b2e6d2f9925"
            }
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "type": "GIT"
        },
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "last_affected": "72f157be2f81910ae759bfe2e5c2256fc4625645"
            },
            {
              "last_affected": "9e9fe58a92a46c6d154d2901735bf230d91b8507"
            },
            {
              "last_affected": "adc1ec6cdc20d430aa01b86497220709b9149466"
            },
            {
              "last_affected": "b54033eb1cfd77aba471269ddd804ed8d3e35dea"
            },
            {
              "last_affected": "c9e82cb34c3c2ee895af01bc899c6ed0bc6eb04a"
            },
            {
              "last_affected": "5eef9b51114fcc65651d671add52f267f91b9451"
            }
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "type": "GIT"
        },
        {
          "events": [
            {
              "introduced": "3.16.52"
            },
            {
              "fixed": "3.17"
            }
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "type": "GIT"
        },
        {
          "events": [
            {
              "introduced": "4.4.163"
            },
            {
              "fixed": "4.5"
            }
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "type": "GIT"
        },
        {
          "events": [
            {
              "introduced": "3.18.101"
            },
            {
              "fixed": "3.19"
            }
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "type": "GIT"
        },
        {
          "events": [
            {
              "introduced": "4.1.52"
            },
            {
              "fixed": "4.2"
            }
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "type": "GIT"
        },
        {
          "events": [
            {
              "introduced": "4.4.123"
            },
            {
              "fixed": "4.5"
            }
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "type": "GIT"
        },
        {
          "events": [
            {
              "introduced": "4.9.89"
            },
            {
              "fixed": "4.10"
            }
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "type": "GIT"
        }
      ]
    },
    {
      "package": {
        "ecosystem": "Linux",
        "name": "Kernel"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "4.14.0"
            },
            {
              "fixed": "7.1.6"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "database_specific": {
    "cna_assigner": "Linux",
    "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/64xxx/CVE-2026-64581.json"
  },
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nxfrm: fix sk_dst_cache double-free in xfrm_user_policy()\n\nxfrm_user_policy() clears the socket dst cache with __sk_dst_reset(),\ni.e. the non-atomic __sk_dst_set(sk, NULL): it reads sk_dst_cache with\nrcu_dereference_protected(), stores NULL and dst_release()s the old dst.\nThat is only safe if no other thread modifies sk_dst_cache concurrently.\n\nFor a connected UDP socket that does not hold: the transmit fast path\n(udp_sendmsg -\u003e sk_dst_check -\u003e sk_dst_reset) resets the cache locklessly\nwith an atomic xchg(). A per-socket policy change racing a send can make\nboth sides observe the same old dst and each dst_release() it, dropping\nthe socket's single reference twice and freeing the xfrm_dst bundle while\nit is still referenced:\n\n  BUG: KASAN: slab-use-after-free in dst_release\n  Write of size 4 at addr ffff88801897b6c0 by task exploit/155\n  Call Trace:\n   ...\n   dst_release (... ./include/linux/rcuref.h:109)\n   xfrm_user_policy (./include/net/sock.h:2239 ./include/net/sock.h:2256 net/xfrm/xfrm_state.c:3053)\n   do_ip_setsockopt (net/ipv4/ip_sockglue.c:1347)\n   ip_setsockopt (net/ipv4/ip_sockglue.c:1417)\n   do_sock_setsockopt (net/socket.c:2368)\n   __sys_setsockopt (net/socket.c:2393)\n   __x64_sys_setsockopt (net/socket.c:2396)\n   do_syscall_64 (arch/x86/entry/syscall_64.c:94)\n   entry_SYSCALL_64_after_hwframe (arch/x86/entry/entry_64.S:121)\n\nReachable by an unprivileged user via a user+network namespace.\n\nUse the atomic sk_dst_reset() so the cache is cleared and released with a\nsingle xchg(): whichever side wins releases the dst once, the other sees\nNULL and does nothing. Behaviour is otherwise unchanged.",
  "id": "CVE-2026-64581",
  "modified": "2026-08-09T03:30:13.428230845Z",
  "published": "2026-08-05T08:09:35.556Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/96b678d08268b5f5c6fc99d4289d9b7e334fc683"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/c283e9ada7fcb7dd4b10592623086b2e6d2f9925"
    },
    {
      "type": "ADVISORY",
      "url": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/64xxx/CVE-2026-64581.json"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-64581"
    },
    {
      "type": "PACKAGE",
      "url": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git"
    }
  ],
  "schema_version": "1.8.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
      "type": "CVSS_V3"
    }
  ],
  "summary": "xfrm: fix sk_dst_cache double-free in xfrm_user_policy()"
}