{
  "affected": [
    {
      "ranges": [
        {
          "events": [
            {
              "introduced": "438b1f668ad58f46ce699bb48e4698a7839e3f9e"
            },
            {
              "fixed": "bca6386dc08750fc7cdcbc7683473748ba3114b9"
            }
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "type": "GIT"
        },
        {
          "events": [
            {
              "introduced": "3733fce2871c9bca9dd18a1a23b1432ea215a094"
            },
            {
              "fixed": "91cc13978ab0bc6f669139f53e7e613a860d10e0"
            }
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "type": "GIT"
        },
        {
          "events": [
            {
              "introduced": "069daad4f2ae9c5c108131995529d5f02392c446"
            },
            {
              "fixed": "d14ae8ef88c2c6590e107db61b6adce148cec7b3"
            },
            {
              "fixed": "3e52417318473782012b236d0325bf7d2266a597"
            }
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "type": "GIT"
        },
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "last_affected": "b66920a3348c0f63ba18365248fa21fbf0b3a937"
            },
            {
              "last_affected": "33a3149dd81a1e2f52b80ee1e0fc380b39f3d028"
            }
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "type": "GIT"
        },
        {
          "events": [
            {
              "introduced": "6.12.83"
            },
            {
              "fixed": "6.12.93"
            }
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "type": "GIT"
        },
        {
          "events": [
            {
              "introduced": "6.18.24"
            },
            {
              "fixed": "6.18.35"
            }
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "type": "GIT"
        },
        {
          "events": [
            {
              "introduced": "6.6.136"
            },
            {
              "fixed": "6.7"
            }
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "type": "GIT"
        },
        {
          "events": [
            {
              "introduced": "6.19.14"
            },
            {
              "fixed": "6.20"
            }
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "type": "GIT"
        }
      ]
    },
    {
      "package": {
        "ecosystem": "Linux",
        "name": "Kernel"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "6.12.93"
            }
          ],
          "type": "ECOSYSTEM"
        },
        {
          "events": [
            {
              "introduced": "6.13.0"
            },
            {
              "fixed": "6.18.35"
            }
          ],
          "type": "ECOSYSTEM"
        },
        {
          "events": [
            {
              "introduced": "6.19.0"
            },
            {
              "fixed": "7.0.12"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "database_specific": {
    "cna_assigner": "Linux",
    "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/64xxx/CVE-2026-64525.json"
  },
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nxfrm: move policy_bydst RCU sync from per-netns .exit to .pre_exit\n\nThe struct pernet_operations docstring in include/net/net_namespace.h\nexplicitly warns against blocking RCU primitives in .exit handlers:\n\n    Exit methods using blocking RCU primitives, such as\n    synchronize_rcu(), should be implemented via exit_batch.\n    [...]\n    Please, avoid synchronize_rcu() at all, where it's possible.\n\n    Note that a combination of pre_exit() and exit() can\n    be used, since a synchronize_rcu() is guaranteed between\n    the calls.\n\nxfrm_policy_fini() violates this: it calls synchronize_rcu() before\nfreeing the policy_bydst hash tables (so no RCU reader is mid-\ntraversal at free time), but runs from xfrm_net_ops.exit -- once per\nnamespace -- so a cleanup_net() of N namespaces pays N full RCU\ngrace periods serially.\n\nUse the documented pre_exit/exit split. Move the policy flush (and\nthe workqueue drains it depends on) into a new .pre_exit handler;\nxfrm_policy_fini() then runs in .exit and frees the hash tables\nafter the synchronize_rcu_expedited() that cleanup_net() guarantees\nbetween the two phases. Providing O(1) RCU grace periods per batch\ninstead of O(N).\n\nObserved on Linux 6.18 with a workload doing unshare(CLONE_NEWNET)\nat ~13/sec sustained: cleanup_net() and the netns_wq rescuer kthread\nboth stuck in xfrm_policy_fini()'s synchronize_rcu(), \u003e300k struct\nnet accumulated in the cleanup queue, Percpu in /proc/meminfo climbed\nto 130+ GB on 256-CPU hosts, and memcg OOMs followed. setup_net and\n__put_net counts were balanced, ruling out a refcount leak.",
  "id": "CVE-2026-64525",
  "modified": "2026-08-12T03:51:25.627974261Z",
  "published": "2026-07-25T09:20:49.256Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/3e52417318473782012b236d0325bf7d2266a597"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/91cc13978ab0bc6f669139f53e7e613a860d10e0"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/bca6386dc08750fc7cdcbc7683473748ba3114b9"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/d14ae8ef88c2c6590e107db61b6adce148cec7b3"
    },
    {
      "type": "ADVISORY",
      "url": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/64xxx/CVE-2026-64525.json"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-64525"
    },
    {
      "type": "PACKAGE",
      "url": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git"
    }
  ],
  "schema_version": "1.9.0",
  "summary": "xfrm: move policy_bydst RCU sync from per-netns .exit to .pre_exit"
}