{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "Documentation/netlink/specs/handshake.yaml",
            "net/handshake/genl.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "25fb53e43ec006ac69b9e825a7e8a11d63a6083e",
              "status": "affected",
              "version": "3b3009ea8abb713b022d94fba95ec270cf6e7eae",
              "versionType": "git"
            },
            {
              "lessThan": "b6557f912509abe8e70223373dd7a44d1d4a0d6c",
              "status": "affected",
              "version": "3b3009ea8abb713b022d94fba95ec270cf6e7eae",
              "versionType": "git"
            },
            {
              "lessThan": "67cec2f1eb9e58719d622e92e2278ceda72dbd85",
              "status": "affected",
              "version": "3b3009ea8abb713b022d94fba95ec270cf6e7eae",
              "versionType": "git"
            },
            {
              "lessThan": "4dafc411948469277b276724c3b2b4408c02c04c",
              "status": "affected",
              "version": "3b3009ea8abb713b022d94fba95ec270cf6e7eae",
              "versionType": "git"
            },
            {
              "lessThan": "81246a65303d9635266b1334490142caaf86a11f",
              "status": "affected",
              "version": "3b3009ea8abb713b022d94fba95ec270cf6e7eae",
              "versionType": "git"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "Documentation/netlink/specs/handshake.yaml",
            "net/handshake/genl.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "6.4"
            },
            {
              "lessThan": "6.4",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.6.*",
              "status": "unaffected",
              "version": "6.6.145",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.12.*",
              "status": "unaffected",
              "version": "6.12.97",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.18.*",
              "status": "unaffected",
              "version": "6.18.40",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "7.1.*",
              "status": "unaffected",
              "version": "7.1.5",
              "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": "6.6.145",
                  "versionStartIncluding": "6.4",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.12.97",
                  "versionStartIncluding": "6.4",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.18.40",
                  "versionStartIncluding": "6.4",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.1.5",
                  "versionStartIncluding": "6.4",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.2",
                  "versionStartIncluding": "6.4",
                  "vulnerable": true
                }
              ],
              "negate": false,
              "operator": "OR"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nhandshake: Require admin permission for DONE command\n\nACCEPT and DONE are the two downcalls of the handshake genl\nfamily, both intended for use by the trusted handshake agent\n(tlshd). ACCEPT already requires GENL_ADMIN_PERM; DONE has\nno privilege check at all.\n\nThe fd-lookup in handshake_nl_done_doit() only confirms that\nsome pending handshake request exists for the supplied sockfd;\nit does not authenticate the sender. An unprivileged process\nthat guesses or observes a valid sockfd can therefore submit\na DONE with HANDSHAKE_A_DONE_STATUS == 0, leaving the kernel\nconsumer to proceed as if the handshake succeeded. A non-zero\nstatus on a forged DONE tears down a legitimate in-flight\nhandshake before tlshd can report its real result."
        }
      ],
      "metrics": [
        {
          "cvssV3_1": {
            "baseScore": 7.8,
            "baseSeverity": "HIGH",
            "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
            "version": "3.1"
          },
          "scenarios": [
            {
              "lang": "en",
              "value": "AV:L - Exploitation requires sending a HANDSHAKE_CMD_DONE generic-netlink message via a local netlink socket to handshake_nl_done_doit(); although nfsd and nvmet-tcp are network-facing, the vulnerable control-plane downcall is not reachable from remote packets.\nAC:L - Once a process holds a sockfd for a socket with a pending handshake request, forging DONE with status 0 or a failure status is a single deterministic netlink operation; the commit describes sockfd guessing/observation as sufficient and no special timing beyond normal concurrency is required.\nPR:L - Before the fix, HANDSHAKE_CMD_DONE lacked GENL_ADMIN_PERM while ACCEPT required it, so any unprivileged local user with netlink access could invoke the handler without CAP_NET_ADMIN in the initial user namespace or any other elevated capability.\nUI:N - Exploitation does not require victim interaction such as opening files or mounting filesystems; the attacker sends a forged DONE netlink message directly to complete or abort an in-flight kernel handshake.\nS:U - Impact is confined to kernel TLS handshake state for local socket consumers (NFS RPC-over-TLS, NVMe-oF TCP TLS); it does not cross a VM, container, or IOMMU security boundary into a different authority.\nC:H - A forged DONE with HANDSHAKE_A_DONE_STATUS==0 makes kernel consumers proceed as if tlshd completed TLS successfully, bypassing X.509/PSK peer verification on NFS and NVMe-oF TCP sessions and undermining confidentiality of protected network storage traffic.\nI:H - The attacker can supply arbitrary HANDSHAKE_A_DONE_REMOTE_AUTH peer-identity values with a forged success, causing nfsd/nvmet to mark connections as TLS-authenticated and continue I/O under false security assumptions, corrupting integrity of access-control decisions.\nA:H - A forged DONE with non-zero status calls handshake_complete() with an error, tearing down legitimate in-flight handshakes before tlshd reports the real result and denying or disrupting TLS session establishment on NFS/NVMe-oF TCP services."
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-08-17T05:45:16.772Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/25fb53e43ec006ac69b9e825a7e8a11d63a6083e"
        },
        {
          "url": "https://git.kernel.org/stable/c/b6557f912509abe8e70223373dd7a44d1d4a0d6c"
        },
        {
          "url": "https://git.kernel.org/stable/c/67cec2f1eb9e58719d622e92e2278ceda72dbd85"
        },
        {
          "url": "https://git.kernel.org/stable/c/4dafc411948469277b276724c3b2b4408c02c04c"
        },
        {
          "url": "https://git.kernel.org/stable/c/81246a65303d9635266b1334490142caaf86a11f"
        }
      ],
      "title": "handshake: Require admin permission for DONE command",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2026-74270",
    "datePublished": "2026-08-15T05:57:44.195Z",
    "dateReserved": "2026-08-15T05:44:03.879Z",
    "dateUpdated": "2026-08-17T05:45:16.772Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}