bpf: fs/xattr: don't assume the inode is locked in path_unlink/path_rmdir

{
  "id": "7b169b729c1b3ccdf4c3662650b6b544d19cf5596fe4a490089c4f3672cba035",
  "url": "https://osv.dev/vulnerability/CVE-2026-98543",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "bpf: fs/xattr: don't assume the inode is locked in path_unlink/path_rmdir",
    "summary": "In the Linux kernel, the following vulnerability has been resolved: bpf: fs/xattr: don't assume the inode is locked in path_unlink/path_rmdir bpf_lsm_has_d_inode_locked() makes the verifier rewrite bpf_[set|remove]_dentry_xattr() to the _locked variants, which assume that the caller already holds the inode's i_rwsem. The path_unlink and path_rmdir hooks are listed, but security_path_unlink() and security_path_rmdir() run before vfs_unlink()/vfs_rmdir() take the victim inode's i_rwsem, so a sleepable BPF LSM program attached to either hook mutates the victim's xattrs without the lock held. Drop the two path hooks from d_inode_locked_hooks so that the verifier keeps the locking bpf_[set|remove]_dentry_xattr() variants, which take the lock themselves.",
    "evidence": "osv:CVE-2026-98543",
    "products": [
      {
        "name": {
          "value": "Kernel",
          "evidence": "/affected/1/package/name"
        },
        "prerequisites": [],
        "fixed_versions": [
          {
            "value": "6.18.55",
            "evidence": "/affected/1/ranges"
          },
          {
            "value": "7.2.9",
            "evidence": "/affected/1/ranges"
          }
        ],
        "affected_versions": []
      }
    ],
    "severity": "high",
    "structured": {
      "id": "CVE-2026-98543",
      "aliases": [
        "CVE-2026-98543"
      ],
      "metrics": [
        {
          "type": "CVSS_V3",
          "score": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:N/I:L/A:H"
        }
      ],
      "affected": [
        {
          "ranges": [
            {
              "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
              "type": "GIT",
              "events": [
                {
                  "introduced": "56467292794b800164df20c076c409ac548e56ec"
                },
                {
                  "fixed": "7504b677c4370c9e4b153c553ff8831c093b1ff6"
                },
                {
                  "fixed": "640d37fbd34d03af727dbc567f48c0203d1de6b4"
                },
                {
                  "fixed": "35d442ed1f86465e49df3119fb898f985186db13"
                }
              ]
            }
          ],
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-98543.json"
          }
        },
        {
          "ranges": [
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "6.15.0"
                },
                {
                  "fixed": "6.18.55"
                }
              ]
            },
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "6.19.0"
                },
                {
                  "fixed": "7.2.9"
                }
              ]
            }
          ],
          "package": {
            "name": "Kernel",
            "ecosystem": "Linux"
          },
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-98543.json"
          }
        }
      ],
      "modified": "2026-10-28T02:30:48.591008280Z",
      "provider": "osv",
      "references": [
        "https://git.kernel.org/stable/c/35d442ed1f86465e49df3119fb898f985186db13",
        "https://git.kernel.org/stable/c/640d37fbd34d03af727dbc567f48c0203d1de6b4",
        "https://git.kernel.org/stable/c/7504b677c4370c9e4b153c553ff8831c093b1ff6",
        "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/98xxx/CVE-2026-98543.json",
        "https://nvd.nist.gov/vuln/detail/CVE-2026-98543",
        "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/2026/98xxx/CVE-2026-98543.json"
      }
    },
    "related_cves": [
      {
        "value": "CVE-2026-98543",
        "evidence": "/id"
      }
    ],
    "security_relevant": true,
    "severity_evidence": "/severity/0/score"
  },
  "source_id": "core-osv",
  "document_id": 517081,
  "published_at": "2026-10-18T15:18:10.823+00:00"
}