{"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": "2026-10-06T08:45:21.397Z"}, "containers": {"cna": {"providerMetadata": {"orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-10-06T08:45:21.397Z"}, "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-rc4", "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-rc4"}]}]}], "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"}}}}

{}

{"affected": [{"affectedData": [{"defaultStatus": "unaffected", "product": "Linux", "programFiles": ["net/ipv4/tcp_input.c"], "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "vendor": "Linux", "versions": [{"lessThan": "07cacab90290f795bad2e566790f4ba8e84cdf5f", "status": "affected", "version": "31770e34e43d6c8dee129bfee77e56c34e61f0e5", "versionType": "git"}, {"lessThan": "6eb9b697f50b73b9684e466c1e97f4ca8e947a59", "status": "affected", "version": "31770e34e43d6c8dee129bfee77e56c34e61f0e5", "versionType": "git"}, {"lessThan": "b86e1e5a4bbcbbccde8b7a3d3486604b581f6628", "status": "affected", "version": "31770e34e43d6c8dee129bfee77e56c34e61f0e5", "versionType": "git"}, {"lessThan": "1c8448db5cf35a13d82b0c9004ffdb49358883e7", "status": "affected", "version": "31770e34e43d6c8dee129bfee77e56c34e61f0e5", "versionType": "git"}, {"lessThan": "8309dc2cc360056aa9cd2acfbfc25930798c3b66", "status": "affected", "version": "31770e34e43d6c8dee129bfee77e56c34e61f0e5", "versionType": "git"}, {"lessThan": "ff037920c688ae6ca1153fec01e90e6782712455", "status": "affected", "version": "31770e34e43d6c8dee129bfee77e56c34e61f0e5", "versionType": "git"}, {"lessThan": "8205ac5ddb42a1843fa8d6a8c295b5c7f4f8c6ed", "status": "affected", "version": "31770e34e43d6c8dee129bfee77e56c34e61f0e5", "versionType": "git"}, {"lessThan": "f81e6c3fb06327bc49cdd6e559845293ba06a704", "status": "affected", "version": "31770e34e43d6c8dee129bfee77e56c34e61f0e5", "versionType": "git"}]}, {"defaultStatus": "affected", "product": "Linux", "programFiles": ["net/ipv4/tcp_input.c"], "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "vendor": "Linux", "versions": [{"status": "affected", "version": "4.14"}, {"lessThan": "4.14", "status": "unaffected", "version": "0", "versionType": "semver"}, {"lessThanOrEqual": "5.10.*", "status": "unaffected", "version": "5.10.271", "versionType": "semver"}, {"lessThanOrEqual": "5.15.*", "status": "unaffected", "version": "5.15.222", "versionType": "semver"}, {"lessThanOrEqual": "6.1.*", "status": "unaffected", "version": "6.1.189", "versionType": "semver"}, {"lessThanOrEqual": "6.6.*", "status": "unaffected", "version": "6.6.158", "versionType": "semver"}, {"lessThanOrEqual": "6.12.*", "status": "unaffected", "version": "6.12.112", "versionType": "semver"}, {"lessThanOrEqual": "6.18.*", "status": "unaffected", "version": "6.18.54", "versionType": "semver"}, {"lessThanOrEqual": "7.2.*", "status": "unaffected", "version": "7.2.8", "versionType": "semver"}, {"lessThanOrEqual": "*", "status": "unaffected", "version": "7.3-rc4", "versionType": "original_commit_for_fix"}]}], "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"}], "cveTags": [], "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."}], "id": "CVE-2026-98255", "lastModified": "2026-10-06T09:18:14.210", "metrics": {}, "published": "2026-10-06T09:18:14.210", "references": [{"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/07cacab90290f795bad2e566790f4ba8e84cdf5f"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/1c8448db5cf35a13d82b0c9004ffdb49358883e7"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/6eb9b697f50b73b9684e466c1e97f4ca8e947a59"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/8205ac5ddb42a1843fa8d6a8c295b5c7f4f8c6ed"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/8309dc2cc360056aa9cd2acfbfc25930798c3b66"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/b86e1e5a4bbcbbccde8b7a3d3486604b581f6628"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/f81e6c3fb06327bc49cdd6e559845293ba06a704"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/ff037920c688ae6ca1153fec01e90e6782712455"}], "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "vulnStatus": "Received"}

{}

{"affected": [{"configurations": [{"platform": null, "status": "affected", "versions": {"scheme": "code_commit", "value": "[31770e34e43d6c8dee129bfee77e56c34e61f0e5,07cacab90290f795bad2e566790f4ba8e84cdf5f)"}}, {"platform": null, "status": "affected", "versions": {"scheme": "code_commit", "value": "[31770e34e43d6c8dee129bfee77e56c34e61f0e5,6eb9b697f50b73b9684e466c1e97f4ca8e947a59)"}}, {"platform": null, "status": "affected", "versions": {"scheme": "code_commit", "value": "[31770e34e43d6c8dee129bfee77e56c34e61f0e5,b86e1e5a4bbcbbccde8b7a3d3486604b581f6628)"}}, {"platform": null, "status": "affected", "versions": {"scheme": "code_commit", "value": "[31770e34e43d6c8dee129bfee77e56c34e61f0e5,1c8448db5cf35a13d82b0c9004ffdb49358883e7)"}}, {"platform": null, "status": "affected", "versions": {"scheme": "code_commit", "value": "[31770e34e43d6c8dee129bfee77e56c34e61f0e5,8309dc2cc360056aa9cd2acfbfc25930798c3b66)"}}, {"platform": null, "status": "affected", "versions": {"scheme": "code_commit", "value": "[31770e34e43d6c8dee129bfee77e56c34e61f0e5,ff037920c688ae6ca1153fec01e90e6782712455)"}}, {"platform": null, "status": "affected", "versions": {"scheme": "code_commit", "value": "[31770e34e43d6c8dee129bfee77e56c34e61f0e5,8205ac5ddb42a1843fa8d6a8c295b5c7f4f8c6ed)"}}, {"platform": null, "status": "affected", "versions": {"scheme": "code_commit", "value": "[31770e34e43d6c8dee129bfee77e56c34e61f0e5,f81e6c3fb06327bc49cdd6e559845293ba06a704)"}}], "enrichment": {"confidence": 99.0, "confidence_source": "inferred", "scores": [{"score": 99.0, "source": "inferred"}, {"score": 100.0, "source": "matching"}]}, "original": {"product": "Linux", "source": "cna", "vendor": "Linux"}, "product": "linux_kernel", "vendor": "linux"}, {"configurations": [{"platform": null, "status": "affected", "versions": {"scheme": "generic", "value": "4.14"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "generic", "value": "[0,4.14)"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "semver", "value": "[5.10.271,5.11.0)"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "semver", "value": "[5.15.222,5.16.0)"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "semver", "value": "[6.1.189,6.2.0)"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "semver", "value": "[6.6.158,6.7.0)"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "semver", "value": "[6.12.112,6.13.0)"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "semver", "value": "[6.18.54,6.19.0)"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "semver", "value": "[7.2.8,7.3.0)"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "semver", "value": "[7.3-rc4,*]"}}], "enrichment": {"confidence": 99.0, "confidence_source": "inferred", "scores": [{"score": 99.0, "source": "inferred"}, {"score": 100.0, "source": "matching"}]}, "original": {"product": "Linux", "source": "cna", "vendor": "Linux"}, "product": "linux_kernel", "vendor": "linux"}], "created": "2026-10-06T12:45:17.644102+00:00", "updated": "2026-10-06T16:15:02.126781+00:00", "vendors": ["linux", "linux$PRODUCT$linux_kernel"], "weaknesses": ["CWE-20"]}