{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "drivers/net/ovpn/peer.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "d20c181088984b6eaa8d7fe7cb5ab3510988df59",
              "status": "affected",
              "version": "1d36a36f6d5347360ef9681a05f6166683bafd1d",
              "versionType": "git"
            },
            {
              "lessThan": "66745480298775f188b2f5ad266643e85a90f73b",
              "status": "affected",
              "version": "1d36a36f6d5347360ef9681a05f6166683bafd1d",
              "versionType": "git"
            },
            {
              "lessThan": "33ec10567fe14456063daf549fdf1a4f53448e4c",
              "status": "affected",
              "version": "1d36a36f6d5347360ef9681a05f6166683bafd1d",
              "versionType": "git"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "drivers/net/ovpn/peer.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "6.16"
            },
            {
              "lessThan": "6.16",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.18.*",
              "status": "unaffected",
              "version": "6.18.45",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "7.1.*",
              "status": "unaffected",
              "version": "7.1.9",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.2",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "cpeApplicability": [
        {
          "nodes": [
            {
              "cpeMatch": [
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.18.45",
                  "versionStartIncluding": "6.16",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.1.9",
                  "versionStartIncluding": "6.16",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.2",
                  "versionStartIncluding": "6.16",
                  "vulnerable": true
                }
              ],
              "negate": false,
              "operator": "OR"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "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()."
        }
      ],
      "metrics": [
        {
          "cvssV3_1": {
            "baseScore": 9.8,
            "baseSeverity": "CRITICAL",
            "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H",
            "version": "3.1"
          },
          "scenarios": [
            {
              "lang": "en",
              "value": "AV:N - The float-path UAF is reached from ovpn_udp_encap_recv()/ovpn_tcp_rcv() through ovpn_recv(), async AEAD decrypt, and ovpn_peer_endpoints_update(); a remote peer sends authenticated DATA_V2 packets over UDP/TCP to an internet-facing MP-mode OpenVPN gateway.\nAC:L - The remote peer controls float timing (new transport source), packet rate, and concurrent removal via TCP disconnect, UDP socket teardown, or keepalive expiry; netlink PEER_SET vs PEER_DEL races are likewise attacker-synchronized with no luck-dependent layout.\nPR:N - On an internet-facing MP-mode gateway, exploitation needs no Linux credentials on the victim\u2014only an established kernel-installed peer with valid AEAD keys (or namespace CAP_NET_ADMIN for netlink races), matching a remote VPN client rather than host root.\nUI:N - The rehash race is triggered by normal peer traffic and automatic keepalive/socket teardown; no administrator or end-user action on the victim host is required beyond routine VPN server operation.\nS:U - The UAF corrupts ovpn peer hash tables inside the kernel VPN driver; impact remains within the host kernel security domain without crossing VM, container, or IOMMU boundaries.\nC:H - Freed ovpn_peer objects remain linked in by_transp_addr/by_vpn_addr hash tables, so RX/TX lookups dereference recycled kmalloc-1k structures and enable arbitrary kernel-memory reads via attacker-controlled heap reuse.\nI:H - Resurrected hash entries steer traffic to freed peers and subsequent RCU/kref teardown on stale objects provide typical slab-UAF write primitives (refcount, socket, crypto pointer updates) suitable for kernel code execution.\nA:H - Use-after-free on hot datapath peer lookups reliably causes kernel oops/panic or slab corruption on VPN gateways, and remote peers can repeat the race to sustain denial of service."
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-08-25T05:42:08.380Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/d20c181088984b6eaa8d7fe7cb5ab3510988df59"
        },
        {
          "url": "https://git.kernel.org/stable/c/66745480298775f188b2f5ad266643e85a90f73b"
        },
        {
          "url": "https://git.kernel.org/stable/c/33ec10567fe14456063daf549fdf1a4f53448e4c"
        }
      ],
      "title": "ovpn: skip rehash for peers already removed from by_id",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2026-74727",
    "datePublished": "2026-08-22T15:33:17.773Z",
    "dateReserved": "2026-08-15T05:44:03.929Z",
    "dateUpdated": "2026-08-25T05:42:08.380Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}