{
  "affected": [
    {
      "ranges": [
        {
          "events": [
            {
              "introduced": "1d36a36f6d5347360ef9681a05f6166683bafd1d"
            },
            {
              "fixed": "d20c181088984b6eaa8d7fe7cb5ab3510988df59"
            },
            {
              "fixed": "66745480298775f188b2f5ad266643e85a90f73b"
            },
            {
              "fixed": "33ec10567fe14456063daf549fdf1a4f53448e4c"
            }
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "type": "GIT"
        }
      ]
    },
    {
      "package": {
        "ecosystem": "Linux",
        "name": "Kernel"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "6.16.0"
            },
            {
              "fixed": "6.18.45"
            }
          ],
          "type": "ECOSYSTEM"
        },
        {
          "events": [
            {
              "introduced": "6.19.0"
            },
            {
              "fixed": "7.1.9"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "database_specific": {
    "cna_assigner": "Linux",
    "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/74xxx/CVE-2026-74727.json"
  },
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\novpn: skip rehash for peers already removed from by_id\n\novpn_nl_peer_set_doit() resolves the target peer via\novpn_peer_get_by_id() before taking ovpn-\u003elock. In the window between\nthe lookup (which only takes a refcount) and the subsequent\nspin_lock_bh(\u0026ovpn-\u003elock), a concurrent OVPN_CMD_PEER_DEL, keepalive\nexpiry, or socket teardown can take ovpn-\u003elock first, run\novpn_peer_remove() to unhash the peer from all four tables (by_id,\nby_vpn_addr4/6, by_transp_addr) and release the lock. set_doit then\nacquires ovpn-\u003elock and calls ovpn_peer_hash_vpn_ip(), which\nre-inserts the now-removed peer back into the rehashing tables.\n\nThe same race affects the float path: ovpn_peer_endpoints_update()\nholds only a refcount and acquires ovpn-\u003elock very late (after async\nAEAD decrypt and a netlink notification), then rehashes the peer\nin the by_transp_addr table.\n\nThe resurrected peer becomes reachable again from the RX lookup\n(ovpn_peer_get_by_transp_addr) and the TX VPN-IP lookup, even though\nuserspace believes it is gone. Once the data-path refcount drops the\npeer is freed via call_rcu while the hash entries embedded in it\nremain linked, opening a UAF window.\n\nBail out of the rehash when hash_entry_id is unhashed, mirroring\nthe sentinel already used by ovpn_peer_remove() to detect the\nalready-removed state. The check is safe under ovpn-\u003elock, which\nserializes every mutation of hash_entry_id, and is a no-op for the\nadd path because ovpn_peer_add_mp() inserts hash_entry_id before\ncalling ovpn_peer_hash_vpn_ip().",
  "id": "CVE-2026-74727",
  "modified": "2026-08-23T03:42:48.096811690Z",
  "published": "2026-08-22T15:33:17.773Z",
  "references": [
    {
      "type": "PACKAGE",
      "url": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/33ec10567fe14456063daf549fdf1a4f53448e4c"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/66745480298775f188b2f5ad266643e85a90f73b"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/d20c181088984b6eaa8d7fe7cb5ab3510988df59"
    },
    {
      "type": "ADVISORY",
      "url": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/74xxx/CVE-2026-74727.json"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-74727"
    }
  ],
  "schema_version": "1.9.0",
  "summary": "ovpn: skip rehash for peers already removed from by_id"
}