{
    "dataType": "CVE_RECORD",
    "dataVersion": "5.2",
    "cveMetadata": {
        "cveId": "CVE-2026-98255",
        "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "state": "PUBLISHED",
        "assignerShortName": "Linux",
        "dateReserved": "2026-09-25T10:25:14.331Z",
        "datePublished": "2026-10-06T08:45:21.397Z",
        "dateUpdated": "2026-10-19T09:16:26.522Z"
    },
    "containers": {
        "cna": {
            "providerMetadata": {
                "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
                "shortName": "Linux",
                "dateUpdated": "2026-10-19T09:16:26.522Z"
            },
            "descriptions": [
                {
                    "lang": "en",
                    "value": "In the Linux kernel, the following vulnerability has been resolved:\n\ntcp: exclude old ACKs from tcp fast path\n\nExclude old ACKs before SND.UNA from the tcp fast path\nas well as ACKs after SND.NXT.\n\nSuch ACKs will fall through to the slow path, where tcp_ack()\nperforms the appropriate validation and challenge ACK handling\naccording to RFC5961 and Commit 3d501dd326fb1c7 (\"tcp: do not\naccept ACK of bytes we never sent\").\n\nThis prevents old ACKs from being accepted\nor modifying connection state as part of the fast path before\nappropriate ACK validation is applied.\nIn particular, this prevents payload carried by a segment with\nan excessively old ACK from advancing RCV.NXT before the ACK\nis rejected."
                }
            ],
            "affected": [
                {
                    "product": "Linux",
                    "vendor": "Linux",
                    "defaultStatus": "unaffected",
                    "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
                    "programFiles": [
                        "net/ipv4/tcp_input.c"
                    ],
                    "versions": [
                        {
                            "version": "31770e34e43d6c8dee129bfee77e56c34e61f0e5",
                            "lessThan": "07cacab90290f795bad2e566790f4ba8e84cdf5f",
                            "status": "affected",
                            "versionType": "git"
                        },
                        {
                            "version": "31770e34e43d6c8dee129bfee77e56c34e61f0e5",
                            "lessThan": "6eb9b697f50b73b9684e466c1e97f4ca8e947a59",
                            "status": "affected",
                            "versionType": "git"
                        },
                        {
                            "version": "31770e34e43d6c8dee129bfee77e56c34e61f0e5",
                            "lessThan": "b86e1e5a4bbcbbccde8b7a3d3486604b581f6628",
                            "status": "affected",
                            "versionType": "git"
                        },
                        {
                            "version": "31770e34e43d6c8dee129bfee77e56c34e61f0e5",
                            "lessThan": "1c8448db5cf35a13d82b0c9004ffdb49358883e7",
                            "status": "affected",
                            "versionType": "git"
                        },
                        {
                            "version": "31770e34e43d6c8dee129bfee77e56c34e61f0e5",
                            "lessThan": "8309dc2cc360056aa9cd2acfbfc25930798c3b66",
                            "status": "affected",
                            "versionType": "git"
                        },
                        {
                            "version": "31770e34e43d6c8dee129bfee77e56c34e61f0e5",
                            "lessThan": "ff037920c688ae6ca1153fec01e90e6782712455",
                            "status": "affected",
                            "versionType": "git"
                        },
                        {
                            "version": "31770e34e43d6c8dee129bfee77e56c34e61f0e5",
                            "lessThan": "8205ac5ddb42a1843fa8d6a8c295b5c7f4f8c6ed",
                            "status": "affected",
                            "versionType": "git"
                        },
                        {
                            "version": "31770e34e43d6c8dee129bfee77e56c34e61f0e5",
                            "lessThan": "f81e6c3fb06327bc49cdd6e559845293ba06a704",
                            "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_input.c"
                    ],
                    "versions": [
                        {
                            "version": "4.14",
                            "status": "affected"
                        },
                        {
                            "version": "0",
                            "lessThan": "4.14",
                            "status": "unaffected",
                            "versionType": "semver"
                        },
                        {
                            "version": "5.10.271",
                            "lessThanOrEqual": "5.10.*",
                            "status": "unaffected",
                            "versionType": "semver"
                        },
                        {
                            "version": "5.15.222",
                            "lessThanOrEqual": "5.15.*",
                            "status": "unaffected",
                            "versionType": "semver"
                        },
                        {
                            "version": "6.1.189",
                            "lessThanOrEqual": "6.1.*",
                            "status": "unaffected",
                            "versionType": "semver"
                        },
                        {
                            "version": "6.6.158",
                            "lessThanOrEqual": "6.6.*",
                            "status": "unaffected",
                            "versionType": "semver"
                        },
                        {
                            "version": "6.12.112",
                            "lessThanOrEqual": "6.12.*",
                            "status": "unaffected",
                            "versionType": "semver"
                        },
                        {
                            "version": "6.18.54",
                            "lessThanOrEqual": "6.18.*",
                            "status": "unaffected",
                            "versionType": "semver"
                        },
                        {
                            "version": "7.2.8",
                            "lessThanOrEqual": "7.2.*",
                            "status": "unaffected",
                            "versionType": "semver"
                        },
                        {
                            "version": "7.3",
                            "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": "4.14",
                                    "versionEndExcluding": "5.10.271"
                                },
                                {
                                    "vulnerable": true,
                                    "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                                    "versionStartIncluding": "4.14",
                                    "versionEndExcluding": "5.15.222"
                                },
                                {
                                    "vulnerable": true,
                                    "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                                    "versionStartIncluding": "4.14",
                                    "versionEndExcluding": "6.1.189"
                                },
                                {
                                    "vulnerable": true,
                                    "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                                    "versionStartIncluding": "4.14",
                                    "versionEndExcluding": "6.6.158"
                                },
                                {
                                    "vulnerable": true,
                                    "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                                    "versionStartIncluding": "4.14",
                                    "versionEndExcluding": "6.12.112"
                                },
                                {
                                    "vulnerable": true,
                                    "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                                    "versionStartIncluding": "4.14",
                                    "versionEndExcluding": "6.18.54"
                                },
                                {
                                    "vulnerable": true,
                                    "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                                    "versionStartIncluding": "4.14",
                                    "versionEndExcluding": "7.2.8"
                                },
                                {
                                    "vulnerable": true,
                                    "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                                    "versionStartIncluding": "4.14",
                                    "versionEndExcluding": "7.3"
                                }
                            ]
                        }
                    ]
                }
            ],
            "references": [
                {
                    "url": "https://git.kernel.org/stable/c/07cacab90290f795bad2e566790f4ba8e84cdf5f"
                },
                {
                    "url": "https://git.kernel.org/stable/c/6eb9b697f50b73b9684e466c1e97f4ca8e947a59"
                },
                {
                    "url": "https://git.kernel.org/stable/c/b86e1e5a4bbcbbccde8b7a3d3486604b581f6628"
                },
                {
                    "url": "https://git.kernel.org/stable/c/1c8448db5cf35a13d82b0c9004ffdb49358883e7"
                },
                {
                    "url": "https://git.kernel.org/stable/c/8309dc2cc360056aa9cd2acfbfc25930798c3b66"
                },
                {
                    "url": "https://git.kernel.org/stable/c/ff037920c688ae6ca1153fec01e90e6782712455"
                },
                {
                    "url": "https://git.kernel.org/stable/c/8205ac5ddb42a1843fa8d6a8c295b5c7f4f8c6ed"
                },
                {
                    "url": "https://git.kernel.org/stable/c/f81e6c3fb06327bc49cdd6e559845293ba06a704"
                }
            ],
            "title": "tcp: exclude old ACKs from tcp fast path",
            "x_generator": {
                "engine": "bippy-1.2.0"
            }
        }
    }
}