FKIE_CVE-2026-45918

Vulnerability from fkie_nvd - Published: 2026-05-27 14:17 - Updated: 2026-06-24 17:22
Severity
5.5 (Medium) - CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
Summary
In the Linux kernel, the following vulnerability has been resolved: ovpn: tcp - don't deref NULL sk_socket member after tcp_close() When deleting a peer in case of keepalive expiration, the peer is removed from the OpenVPN hashtable and is temporary inserted in a "release list" for further processing. This happens in: ovpn_peer_keepalive_work() unlock_ovpn(release_list) This processing includes detaching from the socket being used to talk to this peer, by restoring its original proto and socket ops/callbacks. In case of TCP it may happen that, while the peer is sitting in the release list, userspace decides to close the socket. This will result in a concurrent execution of: tcp_close(sk) __tcp_close(sk) sock_orphan(sk) sk_set_socket(sk, NULL) The last function call will set sk->sk_socket to NULL. When the releasing routine is resumed, ovpn_tcp_socket_detach() will attempt to dereference sk->sk_socket to restore its original ops member. This operation will crash due to sk->sk_socket being NULL. Fix this race condition by testing-and-accessing sk->sk_socket atomically under sk->sk_callback_lock.
References
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/94560267d6c41b1ff3fafbab726e3f8a55a6af34Patch
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/b9142cf4e066c825ec68752a7dcaceda700bbe26Patch
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/f998b2c4bec487063a586695159f9a1856e81c56Patch
Impacted products
Vendor Product Version
linux linux_kernel *
linux linux_kernel *
To clipboard 

{
  "affected": [
    {
      "affectedData": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "drivers/net/ovpn/tcp.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "f998b2c4bec487063a586695159f9a1856e81c56",
              "status": "affected",
              "version": "11851cbd60ea1e5abbd97619d69845ead99303d6",
              "versionType": "git"
            },
            {
              "lessThan": "b9142cf4e066c825ec68752a7dcaceda700bbe26",
              "status": "affected",
              "version": "11851cbd60ea1e5abbd97619d69845ead99303d6",
              "versionType": "git"
            },
            {
              "lessThan": "94560267d6c41b1ff3fafbab726e3f8a55a6af34",
              "status": "affected",
              "version": "11851cbd60ea1e5abbd97619d69845ead99303d6",
              "versionType": "git"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "drivers/net/ovpn/tcp.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": "6.18.14",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.19.*",
              "status": "unaffected",
              "version": "6.19.4",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.0",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    }
  ],
  "configurations": [
    {
      "nodes": [
        {
          "cpeMatch": [
            {
              "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
              "matchCriteriaId": "974ECCCC-3CBB-4A66-9A34-82621077D7F4",
              "versionEndExcluding": "6.18.14",
              "versionStartIncluding": "6.16",
              "vulnerable": true
            },
            {
              "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
              "matchCriteriaId": "672A3E79-EC03-479D-8503-361DFBDC8092",
              "versionEndExcluding": "6.19.4",
              "versionStartIncluding": "6.19",
              "vulnerable": true
            }
          ],
          "negate": false,
          "operator": "OR"
        }
      ]
    }
  ],
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "In the Linux kernel, the following vulnerability has been resolved:\n\novpn: tcp - don\u0027t deref NULL sk_socket member after tcp_close()\n\nWhen deleting a peer in case of keepalive expiration, the peer is\nremoved from the OpenVPN hashtable and is temporary inserted in a\n\"release list\" for further processing.\n\nThis happens in:\novpn_peer_keepalive_work()\n  unlock_ovpn(release_list)\n\nThis processing includes detaching from the socket being used to\ntalk to this peer, by restoring its original proto and socket\nops/callbacks.\n\nIn case of TCP it may happen that, while the peer is sitting in\nthe release list, userspace decides to close the socket.\nThis will result in a concurrent execution of:\n\ntcp_close(sk)\n  __tcp_close(sk)\n    sock_orphan(sk)\n      sk_set_socket(sk, NULL)\n\nThe last function call will set sk-\u003esk_socket to NULL.\n\nWhen the releasing routine is resumed, ovpn_tcp_socket_detach()\nwill attempt to dereference sk-\u003esk_socket to restore its original\nops member. This operation will crash due to sk-\u003esk_socket being NULL.\n\nFix this race condition by testing-and-accessing\nsk-\u003esk_socket atomically under sk-\u003esk_callback_lock."
    }
  ],
  "id": "CVE-2026-45918",
  "lastModified": "2026-06-24T17:22:46.393",
  "metrics": {
    "cvssMetricV31": [
      {
        "cvssData": {
          "attackComplexity": "LOW",
          "attackVector": "LOCAL",
          "availabilityImpact": "HIGH",
          "baseScore": 5.5,
          "baseSeverity": "MEDIUM",
          "confidentialityImpact": "NONE",
          "integrityImpact": "NONE",
          "privilegesRequired": "LOW",
          "scope": "UNCHANGED",
          "userInteraction": "NONE",
          "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H",
          "version": "3.1"
        },
        "exploitabilityScore": 1.8,
        "impactScore": 3.6,
        "source": "nvd@nist.gov",
        "type": "Primary"
      }
    ]
  },
  "published": "2026-05-27T14:17:06.690",
  "references": [
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "tags": [
        "Patch"
      ],
      "url": "https://git.kernel.org/stable/c/94560267d6c41b1ff3fafbab726e3f8a55a6af34"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "tags": [
        "Patch"
      ],
      "url": "https://git.kernel.org/stable/c/b9142cf4e066c825ec68752a7dcaceda700bbe26"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "tags": [
        "Patch"
      ],
      "url": "https://git.kernel.org/stable/c/f998b2c4bec487063a586695159f9a1856e81c56"
    }
  ],
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
  "vulnStatus": "Undergoing Analysis",
  "weaknesses": [
    {
      "description": [
        {
          "lang": "en",
          "value": "CWE-476"
        }
      ],
      "source": "nvd@nist.gov",
      "type": "Primary"
    }
  ]
}


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