ovl: fix null pointer dereference in ovl_permission()

{
  "id": "971d52f4bb9700fb83283df14b0224baccf9c085c61384b06726dcd41cbbf876",
  "url": "https://osv.dev/vulnerability/CVE-2023-53260",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "ovl: fix null pointer dereference in ovl_permission()",
    "summary": "In the Linux kernel, the following vulnerability has been resolved: ovl: fix null pointer dereference in ovl_permission() Following process: P1 P2 path_lookupat link_path_walk inode_permission ovl_permission ovl_i_path_real(inode, &realpath) path->dentry = ovl_i_dentry_upper(inode) drop_cache __dentry_kill(ovl_dentry) iput(ovl_inode) ovl_destroy_inode(ovl_inode) dput(oi->__upperdentry) dentry_kill(upperdentry) dentry_unlink_inode upperdentry->d_inode = NULL realinode = d_inode(realpath.dentry) // return NULL inode_permission(realinode) inode->i_sb // NULL pointer dereference , will trigger an null pointer dereference at realinode: [ 335.664979] BUG: kernel NULL pointer dereference, address: 0000000000000002 [ 335.668032] CPU: 0 PID: 2592 Comm: ls Not tainted 6.3.0 [ 335.669956] RIP: 0010:inode_permission+0x33/0x2c0 [ 335.678939] Call Trace: [ 335.679165] [ 335.679371] ovl_permission+0xde/0x320 [ 335.679723] inode_permission+0x15e/0x2c0 [ 335.680090] link_path_walk+0x115/0x550 [ 335.680771] path_lookupat.isra.0+0xb2/0x200 [ 335.681170] filename_lookup+0xda/0x240 [ 335.681922] vfs_statx+0xa6/0x1f0 [ 335.682233] vfs_fstatat+0x7b/0xb0 Fetch a reproducer in [Link]. Use the helper ovl_i_path_realinode() to get realinode and then do non-nullptr checking.",
    "evidence": "osv:CVE-2023-53260",
    "products": [
      {
        "name": {
          "value": "Kernel",
          "evidence": "/affected/1/package/name"
        },
        "prerequisites": [],
        "fixed_versions": [
          {
            "value": "6.1.43",
            "evidence": "/affected/1/ranges"
          },
          {
            "value": "6.4.4",
            "evidence": "/affected/1/ranges"
          }
        ],
        "affected_versions": []
      }
    ],
    "severity": "medium",
    "structured": {
      "id": "CVE-2023-53260",
      "aliases": [
        "CVE-2023-53260"
      ],
      "metrics": [
        {
          "type": "CVSS_V3",
          "score": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H"
        }
      ],
      "affected": [
        {
          "ranges": [
            {
              "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
              "type": "GIT",
              "events": [
                {
                  "introduced": "4b7791b2e95805eaa9568761741d33cf929c930c"
                },
                {
                  "fixed": "53dd2ca2c02fdcfe3aad2345091d371063f97d17"
                },
                {
                  "fixed": "69f9ae7edf9ec0ff500429101923347fcba5c8c4"
                },
                {
                  "fixed": "1a73f5b8f079fd42a544c1600beface50c63af7c"
                }
              ]
            }
          ],
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2023-53260.json"
          }
        },
        {
          "ranges": [
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "5.19.0"
                },
                {
                  "fixed": "6.1.43"
                }
              ]
            },
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "6.2.0"
                },
                {
                  "fixed": "6.4.4"
                }
              ]
            }
          ],
          "package": {
            "name": "Kernel",
            "ecosystem": "Linux"
          },
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2023-53260.json"
          }
        }
      ],
      "modified": "2026-10-28T02:30:27.284751831Z",
      "provider": "osv",
      "references": [
        "https://git.kernel.org/stable/c/1a73f5b8f079fd42a544c1600beface50c63af7c",
        "https://git.kernel.org/stable/c/53dd2ca2c02fdcfe3aad2345091d371063f97d17",
        "https://git.kernel.org/stable/c/69f9ae7edf9ec0ff500429101923347fcba5c8c4",
        "https://github.com/CVEProject/cvelistV5/tree/main/cves/2023/53xxx/CVE-2023-53260.json",
        "https://nvd.nist.gov/vuln/detail/CVE-2023-53260",
        "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git"
      ],
      "provider_metadata": {
        "cna_assigner": "Linux",
        "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2023/53xxx/CVE-2023-53260.json"
      }
    },
    "related_cves": [
      {
        "value": "CVE-2023-53260",
        "evidence": "/id"
      }
    ],
    "security_relevant": true,
    "severity_evidence": "/severity/0/score"
  },
  "source_id": "core-osv",
  "document_id": 493620,
  "published_at": "2025-09-15T14:46:31.919+00:00"
}