{
  "affected": [
    {
      "ranges": [
        {
          "events": [
            {
              "introduced": "1da177e4c3f41524e886b7f1b8a0c1fc7321cac2"
            },
            {
              "fixed": "3e8b25f32f2f35549d03d77da030a24a45bdef5b"
            },
            {
              "fixed": "750a33f417f3d196b86375f8d9f8938bacf130fe"
            },
            {
              "fixed": "317843d5355062020649124eb4a0d7acbcc3f53e"
            },
            {
              "fixed": "b256d055da47258e63f8b40965f276c5f23d229a"
            },
            {
              "fixed": "3989740fa4978e1d2d51ecc62be1b01093e104ad"
            },
            {
              "fixed": "abc10f85a3965ac14b9ed7ad3e67b35604a63aa3"
            },
            {
              "fixed": "5fbbb1ff936d7ff9528d929c1549977e8123d8a8"
            },
            {
              "fixed": "922814879542c2e397b0e9641fd36b8202a8e555"
            }
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "type": "GIT"
        }
      ]
    },
    {
      "package": {
        "ecosystem": "Linux",
        "name": "Kernel"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "2.6.12"
            },
            {
              "fixed": "5.10.253"
            }
          ],
          "type": "ECOSYSTEM"
        },
        {
          "events": [
            {
              "introduced": "5.11.0"
            },
            {
              "fixed": "5.15.203"
            }
          ],
          "type": "ECOSYSTEM"
        },
        {
          "events": [
            {
              "introduced": "5.16.0"
            },
            {
              "fixed": "6.1.168"
            }
          ],
          "type": "ECOSYSTEM"
        },
        {
          "events": [
            {
              "introduced": "6.2.0"
            },
            {
              "fixed": "6.6.134"
            }
          ],
          "type": "ECOSYSTEM"
        },
        {
          "events": [
            {
              "introduced": "6.7.0"
            },
            {
              "fixed": "6.12.81"
            }
          ],
          "type": "ECOSYSTEM"
        },
        {
          "events": [
            {
              "introduced": "6.13.0"
            },
            {
              "fixed": "6.18.22"
            }
          ],
          "type": "ECOSYSTEM"
        },
        {
          "events": [
            {
              "introduced": "6.19.0"
            },
            {
              "fixed": "6.19.12"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "database_specific": {
    "cna_assigner": "Linux",
    "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/43xxx/CVE-2026-43050.json"
  },
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\natm: lec: fix use-after-free in sock_def_readable()\n\nA race condition exists between lec_atm_close() setting priv-\u003elecd\nto NULL and concurrent access to priv-\u003elecd in send_to_lecd(),\nlec_handle_bridge(), and lec_atm_send(). When the socket is freed\nvia RCU while another thread is still using it, a use-after-free\noccurs in sock_def_readable() when accessing the socket's wait queue.\n\nThe root cause is that lec_atm_close() clears priv-\u003elecd without\nany synchronization, while callers dereference priv-\u003elecd without\nany protection against concurrent teardown.\n\nFix this by converting priv-\u003elecd to an RCU-protected pointer:\n- Mark priv-\u003elecd as __rcu in lec.h\n- Use rcu_assign_pointer() in lec_atm_close() and lecd_attach()\n  for safe pointer assignment\n- Use rcu_access_pointer() for NULL checks that do not dereference\n  the pointer in lec_start_xmit(), lec_push(), send_to_lecd() and\n  lecd_attach()\n- Use rcu_read_lock/rcu_dereference/rcu_read_unlock in send_to_lecd(),\n  lec_handle_bridge() and lec_atm_send() to safely access lecd\n- Use rcu_assign_pointer() followed by synchronize_rcu() in\n  lec_atm_close() to ensure all readers have completed before\n  proceeding. This is safe since lec_atm_close() is called from\n  vcc_release() which holds lock_sock(), a sleeping lock.\n- Remove the manual sk_receive_queue drain from lec_atm_close()\n  since vcc_destroy_socket() already drains it after lec_atm_close()\n  returns.\n\nv2: Switch from spinlock + sock_hold/put approach to RCU to properly\n    fix the race. The v1 spinlock approach had two issues pointed out\n    by Eric Dumazet:\n    1. priv-\u003elecd was still accessed directly after releasing the\n       lock instead of using a local copy.\n    2. The spinlock did not prevent packets being queued after\n       lec_atm_close() drains sk_receive_queue since timer and\n       workqueue paths bypass netif_stop_queue().\n\nNote: Syzbot patch testing was attempted but the test VM terminated\n    unexpectedly with \"Connection to localhost closed by remote host\",\n    likely due to a QEMU AHCI emulation issue unrelated to this fix.\n    Compile testing with \"make W=1 net/atm/lec.o\" passes cleanly.",
  "id": "CVE-2026-43050",
  "modified": "2026-07-08T05:37:04.418006015Z",
  "published": "2026-05-01T14:15:44.542Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/317843d5355062020649124eb4a0d7acbcc3f53e"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/3989740fa4978e1d2d51ecc62be1b01093e104ad"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/3e8b25f32f2f35549d03d77da030a24a45bdef5b"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/5fbbb1ff936d7ff9528d929c1549977e8123d8a8"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/750a33f417f3d196b86375f8d9f8938bacf130fe"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/922814879542c2e397b0e9641fd36b8202a8e555"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/abc10f85a3965ac14b9ed7ad3e67b35604a63aa3"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/b256d055da47258e63f8b40965f276c5f23d229a"
    },
    {
      "type": "ADVISORY",
      "url": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/43xxx/CVE-2026-43050.json"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-43050"
    },
    {
      "type": "PACKAGE",
      "url": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git"
    }
  ],
  "schema_version": "1.7.5",
  "summary": "atm: lec: fix use-after-free in sock_def_readable()"
}