{
    "dataType": "CVE_RECORD",
    "dataVersion": "5.2",
    "cveMetadata": {
        "cveId": "CVE-2026-80738",
        "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "state": "PUBLISHED",
        "assignerShortName": "Linux",
        "dateReserved": "2026-08-26T14:34:25.789Z",
        "datePublished": "2026-09-03T08:21:53.143Z",
        "dateUpdated": "2026-09-04T04:58:23.870Z"
    },
    "containers": {
        "cna": {
            "providerMetadata": {
                "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
                "shortName": "Linux",
                "dateUpdated": "2026-09-04T04:58:23.870Z"
            },
            "descriptions": [
                {
                    "lang": "en",
                    "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nbpf: Check sk_state before sk_protocol in bpf_tcp_*_syncookie\n\nbpf_tcp_gen_syncookie and bpf_tcp_check_syncookie accept a socket pointer\n'sk' with argument type ARG_PTR_TO_BTF_ID_SOCK_COMMON. However, they access\nsk->sk_protocol without validating whether 'sk' represents a full socket.\n\nFix this issue by checking sk->sk_state != TCP_LISTEN before inspecting\nsk->sk_protocol in both bpf_tcp_gen_syncookie and bpf_tcp_check_syncookie.\nSince mini-sockets are never in the TCP_LISTEN state, the condition\nshort-circuits and prevents dereferencing fullsock-specific fields."
                }
            ],
            "metrics": [
                {
                    "cvssV3_1": {
                        "version": "3.1",
                        "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:L",
                        "baseScore": 7.3,
                        "baseSeverity": "HIGH"
                    },
                    "scenarios": [
                        {
                            "lang": "en",
                            "value": "AV:L - The flaw is in bpf_tcp_gen_syncookie/bpf_tcp_check_syncookie BPF helpers invoked only from locally loaded and attached TC clsact or XDP programs via bpf(); per kernel CNA guidance BPF/tc paths are Local even when later triggered by ingress packets.\nAC:L - An attacker who loads the BPF program fully controls passing bpf_skc_lookup_tcp() results (request_sock/TCP_NEW_SYN_RECV or timewait sockets) into the syncookie helpers and can reliably trigger the bad sk_protocol read with crafted SYN/ACK traffic; no uncontrollable races or rare layout are required.\nPR:L - Exploitation requires bpf(BPF_PROG_LOAD) (CAP_BPF, obtainable in user namespaces) plus attaching TC/XDP hooks (CAP_NET_ADMIN via unshare -Urn); no init-namespace root is needed, matching CNA guidance for namespace-reachable net/BPF capabilities.\nUI:N - No victim mount, login, or cooperative action is required; once the attacker loads and attaches their BPF program, sending network packets from their own processes deterministically reaches the vulnerable helper on each matching lookup.\nS:U - Impact is confined to kernel heap disclosure/type confusion within the host kernel security domain; it does not cross VM, container runtime, IOMMU, or other security-authority boundaries.\nC:H - Casting a mini-socket to struct sock and reading sk_protocol performs a fixed-offset out-of-bounds read (~300+ bytes past request_sock/inet_timewait_sock) into adjacent slab memory, leaking kernel heap contents including pointers usable for further local exploitation.\nI:H - This is type confusion between ARG_PTR_TO_BTF_ID_SOCK_COMMON mini-sockets and full struct sock fields; per CNA guidance type confusion is rated High integrity impact even though the immediate bug is a read, because mis-typed socket pointers corrupt the kernel's object model.\nA:L - The primary impact is information disclosure; while the out-of-bounds u16 read usually stays within the slab page, reads near allocation boundaries or under KASAN can fault and oops the kernel, giving at least Low availability impact when uncertain."
                        }
                    ]
                }
            ],
            "affected": [
                {
                    "product": "Linux",
                    "vendor": "Linux",
                    "defaultStatus": "unaffected",
                    "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
                    "programFiles": [
                        "net/core/filter.c"
                    ],
                    "versions": [
                        {
                            "version": "399040847084a69f345e0a52fd62f04654e0fce3",
                            "lessThan": "23f682083aa3fbc0c49667818efd6979a8bc5ac2",
                            "status": "affected",
                            "versionType": "git"
                        },
                        {
                            "version": "399040847084a69f345e0a52fd62f04654e0fce3",
                            "lessThan": "31a420a822ff92e2090bd5d65efe8e34e2d6d9b8",
                            "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/core/filter.c"
                    ],
                    "versions": [
                        {
                            "version": "5.2",
                            "status": "affected"
                        },
                        {
                            "version": "0",
                            "lessThan": "5.2",
                            "status": "unaffected",
                            "versionType": "semver"
                        },
                        {
                            "version": "7.1.9",
                            "lessThanOrEqual": "7.1.*",
                            "status": "unaffected",
                            "versionType": "semver"
                        },
                        {
                            "version": "7.2",
                            "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": "5.2",
                                    "versionEndExcluding": "7.1.9"
                                },
                                {
                                    "vulnerable": true,
                                    "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                                    "versionStartIncluding": "5.2",
                                    "versionEndExcluding": "7.2"
                                }
                            ]
                        }
                    ]
                }
            ],
            "references": [
                {
                    "url": "https://git.kernel.org/stable/c/23f682083aa3fbc0c49667818efd6979a8bc5ac2"
                },
                {
                    "url": "https://git.kernel.org/stable/c/31a420a822ff92e2090bd5d65efe8e34e2d6d9b8"
                }
            ],
            "title": "bpf: Check sk_state before sk_protocol in bpf_tcp_*_syncookie",
            "x_generator": {
                "engine": "bippy-1.2.0"
            }
        }
    }
}