{
    "dataType": "CVE_RECORD",
    "dataVersion": "5.2",
    "cveMetadata": {
        "cveId": "CVE-2025-40075",
        "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "state": "PUBLISHED",
        "assignerShortName": "Linux",
        "dateReserved": "2025-04-16T07:20:57.160Z",
        "datePublished": "2025-10-28T11:48:41.791Z",
        "dateUpdated": "2026-08-05T12:07:34.647Z"
    },
    "containers": {
        "cna": {
            "providerMetadata": {
                "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
                "shortName": "Linux",
                "dateUpdated": "2026-08-05T12:07:34.647Z"
            },
            "descriptions": [
                {
                    "lang": "en",
                    "value": "In the Linux kernel, the following vulnerability has been resolved:\n\ntcp_metrics: use dst_dev_net_rcu()\n\nReplace three dst_dev() with a lockdep enabled helper."
                }
            ],
            "metrics": [
                {
                    "cvssV3_1": {
                        "version": "3.1",
                        "vectorString": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H",
                        "baseScore": 8.1,
                        "baseSeverity": "HIGH"
                    },
                    "scenarios": [
                        {
                            "lang": "en",
                            "value": "AV:N - The three fixed call sites sit in the core TCP metrics cache, reached from `tcp_conn_request()` on an inbound SYN, from `tcp_finish_connect()`, from the TIME-WAIT/LAST-ACK teardown path, and from TCP Fast Open — all driven purely by packets from a remote peer. No local access is needed to reach the vulnerable code.\nAC:H - The stale `dst->dev` window only exists while `dst_dev_put()` is concurrently swapping the device to the blackhole netdev during a route removal or NETDEV_DOWN/UNREGISTER event, which a remote attacker cannot induce or time. The attacker controls only the TCP-connection side of the race.\nPR:N - `tcp_peer_is_proven()` is invoked from `tcp_conn_request()` while processing an unauthenticated SYN, before any application-level credentials exist, and the other paths only require establishing or closing a normal TCP connection. No kernel privilege check or capability gate exists anywhere along the path.\nUI:N - The code runs entirely from softirq/socket context on packet receive and connection teardown; no local user or administrator action is required to trigger it.\nS:U - The unprotected dereference and its consequences are confined to the kernel's own memory and the network stack — the same security authority. There is no VM, IOMMU, or sandbox boundary crossed.\nC:H - A use-after-free read of a released `struct net_device` yields a `struct net` pointer taken from reclaimed memory, which is then used to compute hashes and index the per-namespace metrics cache; attacker-groomed heap contents can be interpreted as kernel structures, enabling disclosure of kernel memory.\nI:H - The bogus `struct net` derived from the freed device is stored into `tm->tcpm_net` and drives `tcpm_new()`/`tcpm_suck_dst()` writes, so freed or attacker-controlled memory is treated as a live namespace object — a UAF of this class is leverageable for controlled kernel writes and control-flow hijack.\nA:H - Dereferencing a freed `net_device` through `dev_net_rcu()` and then using the resulting garbage `struct net` pointer for `net_hash_mix()` and cache lookups leads to an oops or panic, taking down the whole system."
                        }
                    ]
                }
            ],
            "affected": [
                {
                    "product": "Linux",
                    "vendor": "Linux",
                    "defaultStatus": "unaffected",
                    "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
                    "programFiles": [
                        "net/ipv4/tcp_metrics.c"
                    ],
                    "versions": [
                        {
                            "version": "4a6ce2b6f2ecabbddcfe47e7cf61dd0f00b10e36",
                            "lessThan": "4b89397807eb04986427c4786d065e9442834ad4",
                            "status": "affected",
                            "versionType": "git"
                        },
                        {
                            "version": "4a6ce2b6f2ecabbddcfe47e7cf61dd0f00b10e36",
                            "lessThan": "07613a95326ebad2d1b88d883cd72546025a4f3e",
                            "status": "affected",
                            "versionType": "git"
                        },
                        {
                            "version": "4a6ce2b6f2ecabbddcfe47e7cf61dd0f00b10e36",
                            "lessThan": "50c127a69cd6285300931853b352a1918cfa180f",
                            "status": "affected",
                            "versionType": "git"
                        }
                    ]
                },
                {
                    "product": "Linux",
                    "vendor": "Linux",
                    "defaultStatus": "affected",
                    "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
                    "programFiles": [
                        "net/ipv4/tcp_metrics.c"
                    ],
                    "versions": [
                        {
                            "version": "4.13",
                            "status": "affected"
                        },
                        {
                            "version": "0",
                            "lessThan": "4.13",
                            "status": "unaffected",
                            "versionType": "semver"
                        },
                        {
                            "version": "6.12.63",
                            "lessThanOrEqual": "6.12.*",
                            "status": "unaffected",
                            "versionType": "semver"
                        },
                        {
                            "version": "6.17.3",
                            "lessThanOrEqual": "6.17.*",
                            "status": "unaffected",
                            "versionType": "semver"
                        },
                        {
                            "version": "6.18",
                            "lessThanOrEqual": "*",
                            "status": "unaffected",
                            "versionType": "original_commit_for_fix"
                        }
                    ]
                }
            ],
            "cpeApplicability": [
                {
                    "nodes": [
                        {
                            "operator": "OR",
                            "negate": false,
                            "cpeMatch": [
                                {
                                    "vulnerable": true,
                                    "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                                    "versionStartIncluding": "4.13",
                                    "versionEndExcluding": "6.12.63"
                                },
                                {
                                    "vulnerable": true,
                                    "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                                    "versionStartIncluding": "4.13",
                                    "versionEndExcluding": "6.17.3"
                                },
                                {
                                    "vulnerable": true,
                                    "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                                    "versionStartIncluding": "4.13",
                                    "versionEndExcluding": "6.18"
                                }
                            ]
                        }
                    ]
                }
            ],
            "references": [
                {
                    "url": "https://git.kernel.org/stable/c/4b89397807eb04986427c4786d065e9442834ad4"
                },
                {
                    "url": "https://git.kernel.org/stable/c/07613a95326ebad2d1b88d883cd72546025a4f3e"
                },
                {
                    "url": "https://git.kernel.org/stable/c/50c127a69cd6285300931853b352a1918cfa180f"
                }
            ],
            "title": "tcp_metrics: use dst_dev_net_rcu()",
            "x_generator": {
                "engine": "bippy-1.2.0"
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        }
    }
}