{
  "affected": [
    {
      "ranges": [
        {
          "events": [
            {
              "introduced": "8df4bcdb0a4232192b2445256c39b787d58ef14d"
            },
            {
              "fixed": "945a86b21b40fb17183f5b27461baa6f03e2467f"
            }
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "type": "GIT"
        },
        {
          "events": [
            {
              "introduced": "c8efcc786146a951091588e5fa7e3c754850cb3c"
            },
            {
              "fixed": "1ff58dcfcab434ebb51649da33774fbb8e1f7b67"
            },
            {
              "fixed": "e735dbd489e3ea02be78dba991056fe1138be51e"
            },
            {
              "fixed": "75e33deda658c1ab3a9336cbdb1436536f9b3660"
            },
            {
              "fixed": "b003086d76968298f22e7cf62239833b5a3a06b1"
            }
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "type": "GIT"
        },
        {
          "events": [
            {
              "introduced": "6.6.32"
            },
            {
              "fixed": "6.6.143"
            }
          ],
          "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": "6.6.143"
            }
          ],
          "type": "ECOSYSTEM"
        },
        {
          "events": [
            {
              "introduced": "6.7.0"
            },
            {
              "fixed": "6.12.94"
            }
          ],
          "type": "ECOSYSTEM"
        },
        {
          "events": [
            {
              "introduced": "6.9.0"
            },
            {
              "fixed": "6.18.36"
            }
          ],
          "type": "ECOSYSTEM"
        },
        {
          "events": [
            {
              "introduced": "6.13.0"
            },
            {
              "fixed": "7.0.13"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "database_specific": {
    "cna_assigner": "Linux",
    "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/53xxx/CVE-2026-53271.json"
  },
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nksmbd: fix NULL-deref of opinfo-\u003econn in oplock/lease break notifiers\n\nsmb2_oplock_break_noti() and smb2_lease_break_noti() read opinfo-\u003econn\ninto a local with neither READ_ONCE() nor a NULL check.  Both run from\noplock_break() after opinfo_get_list() has dropped ci-\u003em_lock, so a\nconcurrent SMB2 LOGOFF (session_fd_check()) can set op-\u003econn = NULL\nunder ci-\u003em_lock within that window.  ksmbd_conn_r_count_inc(conn) then\nwrites through NULL at offset 0xc4 -- a remotely triggerable oops.\n\nGuard both reads the way compare_guid_key() already does: read\nopinfo-\u003econn with READ_ONCE() and return early if it is NULL, before\nallocating the work struct so nothing leaks.  A NULL conn means the\nclient is gone and the break is moot, so return 0; oplock_break() treats\nthat as success and runs the normal teardown.",
  "id": "CVE-2026-53271",
  "modified": "2026-08-12T03:51:44.497071982Z",
  "published": "2026-06-25T08:39:56.489Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/1ff58dcfcab434ebb51649da33774fbb8e1f7b67"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/75e33deda658c1ab3a9336cbdb1436536f9b3660"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/945a86b21b40fb17183f5b27461baa6f03e2467f"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/b003086d76968298f22e7cf62239833b5a3a06b1"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/e735dbd489e3ea02be78dba991056fe1138be51e"
    },
    {
      "type": "ADVISORY",
      "url": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/53xxx/CVE-2026-53271.json"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-53271"
    },
    {
      "type": "PACKAGE",
      "url": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git"
    }
  ],
  "schema_version": "1.9.0",
  "summary": "ksmbd: fix NULL-deref of opinfo-\u003econn in oplock/lease break notifiers"
}