{
  "affected": [
    {
      "ranges": [
        {
          "events": [
            {
              "introduced": "e2f34481b24db2fd634b5edb0a5bd0e4d38cc6e9"
            },
            {
              "fixed": "cdac6f7e7e428dc70e3b5898ac6999a72ed13993"
            },
            {
              "fixed": "c9b95ef6f5039f19e46c3a521a4fe1752d91dfe9"
            },
            {
              "fixed": "91aeaa7256006d79a37298f5a1df23325db91599"
            },
            {
              "fixed": "3cdacd11b41569ce75b3162142240f2355e04900"
            },
            {
              "fixed": "aab42f0795620cf0d3955a520f571f697d0f9a2a"
            },
            {
              "fixed": "309b44ed684496ed3f9c5715d10b899338623512"
            }
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "type": "GIT"
        }
      ]
    },
    {
      "package": {
        "ecosystem": "Linux",
        "name": "Kernel"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "5.15.0"
            },
            {
              "fixed": "6.1.168"
            }
          ],
          "type": "ECOSYSTEM"
        },
        {
          "events": [
            {
              "introduced": "6.2.0"
            },
            {
              "fixed": "6.6.131"
            }
          ],
          "type": "ECOSYSTEM"
        },
        {
          "events": [
            {
              "introduced": "6.7.0"
            },
            {
              "fixed": "6.12.80"
            }
          ],
          "type": "ECOSYSTEM"
        },
        {
          "events": [
            {
              "introduced": "6.13.0"
            },
            {
              "fixed": "6.18.21"
            }
          ],
          "type": "ECOSYSTEM"
        },
        {
          "events": [
            {
              "introduced": "6.19.0"
            },
            {
              "fixed": "6.19.11"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "database_specific": {
    "cna_assigner": "Linux",
    "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/31xxx/CVE-2026-31477.json"
  },
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nksmbd: fix memory leaks and NULL deref in smb2_lock()\n\nsmb2_lock() has three error handling issues after list_del() detaches\nsmb_lock from lock_list at no_check_cl:\n\n1) If vfs_lock_file() returns an unexpected error in the non-UNLOCK\n   path, goto out leaks smb_lock and its flock because the out:\n   handler only iterates lock_list and rollback_list, neither of\n   which contains the detached smb_lock.\n\n2) If vfs_lock_file() returns -ENOENT in the UNLOCK path, goto out\n   leaks smb_lock and flock for the same reason.  The error code\n   returned to the dispatcher is also stale.\n\n3) In the rollback path, smb_flock_init() can return NULL on\n   allocation failure.  The result is dereferenced unconditionally,\n   causing a kernel NULL pointer dereference.  Add a NULL check to\n   prevent the crash and clean up the bookkeeping; the VFS lock\n   itself cannot be rolled back without the allocation and will be\n   released at file or connection teardown.\n\nFix cases 1 and 2 by hoisting the locks_free_lock()/kfree() to before\nthe if(!rc) check in the UNLOCK branch so all exit paths share one\nfree site, and by freeing smb_lock and flock before goto out in the\nnon-UNLOCK branch.  Propagate the correct error code in both cases.\nFix case 3 by wrapping the VFS unlock in an if(rlock) guard and adding\na NULL check for locks_free_lock(rlock) in the shared cleanup.\n\nFound via call-graph analysis using sqry.",
  "id": "CVE-2026-31477",
  "modified": "2026-07-08T05:37:38.369415263Z",
  "published": "2026-04-22T13:54:05.470Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/309b44ed684496ed3f9c5715d10b899338623512"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/3cdacd11b41569ce75b3162142240f2355e04900"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/91aeaa7256006d79a37298f5a1df23325db91599"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/aab42f0795620cf0d3955a520f571f697d0f9a2a"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/c9b95ef6f5039f19e46c3a521a4fe1752d91dfe9"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/cdac6f7e7e428dc70e3b5898ac6999a72ed13993"
    },
    {
      "type": "ADVISORY",
      "url": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/31xxx/CVE-2026-31477.json"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-31477"
    },
    {
      "type": "PACKAGE",
      "url": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git"
    }
  ],
  "schema_version": "1.7.5",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H",
      "type": "CVSS_V3"
    }
  ],
  "summary": "ksmbd: fix memory leaks and NULL deref in smb2_lock()"
}