{
  "cveId": "CVE-2026-74727",
  "url": "https://patchblox.com/security/cve/CVE-2026-74727",
  "summary": "CVE-2026-74727 is fixed in linux on 1 platform by DEBIAN-CVE-2026-74727 (version 7.1.9-1), released September 4, 2026. It is not reported as exploited. Patch Radar priority: Urgent.",
  "title": "linux: In the Linux kernel, the following vulnerability has been resolved:  ovpn: skip rehash for peers already removed from...",
  "description": "In the Linux kernel, the following vulnerability has been resolved:  ovpn: skip rehash for peers already removed from by_id  ovpn_nl_peer_set_doit() resolves the target peer via ovpn_peer_get_by_id() before taking ovpn-\u003Elock. In the window between the lookup (which only takes a refcount) and the subsequent spin_lock_bh(\u0026ovpn-\u003Elock), a concurrent OVPN_CMD_PEER_DEL, keepalive expiry, or socket teardown can take ovpn-\u003Elock first, run ovpn_peer_remove() to unhash the peer from all four tables (by_id, by_vpn_addr4/6, by_transp_addr) and release the lock. set_doit then acquires ovpn-\u003Elock and calls ovpn_peer_hash_vpn_ip(), which re-inserts the now-removed peer back into the rehashing tables.  The same race affects the float path: ovpn_peer_endpoints_update() holds only a refcount and acquires ovpn-\u003Elock very late (after async AEAD decrypt and a netlink notification), then rehashes the peer in the by_transp_addr table.  The resurrected peer becomes reachable again from the RX lookup (ovpn_peer_get_by_transp_addr) and the TX VPN-IP lookup, even though userspace believes it is gone. Once the data-path refcount drops the peer is freed via call_rcu while the hash entries embedded in it remain linked, opening a UAF window.  Bail out of the rehash when hash_entry_id is unhashed, mirroring the sentinel already used by ovpn_peer_remove() to detect the already-removed state. The check is safe under ovpn-\u003Elock, which serializes every mutation of hash_entry_id, and is a no-op for the add path because ovpn_peer_add_mp() inserts hash_entry_id before calling ovpn_peer_hash_vpn_ip().",
  "published": "2026-08-22T16:16:47Z",
  "severity": "critical",
  "cvss": 9.8,
  "cvssVector": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H",
  "epss": 0.00442,
  "epssPercentile": 0.38682,
  "priority": "Urgent",
  "priorityTier": 2,
  "exploited": false,
  "vendorExploited": false,
  "disclosed": false,
  "fixes": [
    {
      "platform": "linux",
      "product": "linux",
      "release": "Debian 14",
      "fixedVersion": "7.1.9-1",
      "fix": "DEBIAN-CVE-2026-74727",
      "url": "https://patchblox.com/security/fix/linux/debian-cve-2026-74727",
      "released": "2026-09-04T01:46:23Z"
    }
  ],
  "noFixYet": [],
  "dataAsOf": "2026-11-08T19:12:23Z",
  "attribution": {
    "text": "Data: Patchblox Patch Radar",
    "url": "https://patchblox.com/security/patch-radar",
    "terms": "https://patchblox.com/security/patch-radar/use-the-data"
  }
}