{"api_version":"1","generated_at":"2026-07-28T03:02:36+00:00","cve":"CVE-2026-64422","urls":{"html":"https://cve.report/CVE-2026-64422","api":"https://cve.report/api/cve/CVE-2026-64422.json","docs":"https://cve.report/api","cve_org":"https://www.cve.org/CVERecord?id=CVE-2026-64422","nvd":"https://nvd.nist.gov/vuln/detail/CVE-2026-64422"},"summary":{"title":"net: ipv4: bound TCP reordering sysctl writes and MTU probe sizes","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nnet: ipv4: bound TCP reordering sysctl writes and MTU probe sizes\n\nReject invalid `net.ipv4.tcp_reordering` values before they reach TCP\nsocket state. The sysctl is stored as an `int` but copied into the\n`u32` `tp->reordering` field for new sockets, so negative writes wrap\nto large values.\n\nWith `tcp_mtu_probing=2`, the wrapped value can overflow the\n`tcp_mtu_probe()` size calculation and drive the MTU probing path into\nan out-of-bounds read. Route `tcp_reordering` writes through\n`proc_dointvec_minmax()` and require it to be at least 1. Also require\n`tcp_max_reordering` to be at least 1 so the configured maximum cannot\nbecome negative either.\n\nWhen registering the table for a non-init network namespace, relocate\n`extra2` pointers that refer into `init_net.ipv4` so the\n`tcp_reordering` upper bound follows that namespace's\n`tcp_max_reordering`.\n\nHarden `tcp_mtu_probe()` itself by computing `size_needed` as `u64`.\nThis keeps the send queue and window checks from being bypassed through\nsigned integer overflow.","state":"PUBLISHED","assigner":"Linux","published_at":"2026-07-25 10:17:26","updated_at":"2026-07-27 05:16:48"},"problem_types":[],"metrics":[{"version":"3.1","source":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","type":"Secondary","score":"7.1","severity":"HIGH","vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H","data":{"version":"3.1","vectorString":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H","baseScore":7.1,"baseSeverity":"HIGH","attackVector":"LOCAL","attackComplexity":"LOW","privilegesRequired":"LOW","userInteraction":"NONE","scope":"UNCHANGED","confidentialityImpact":"HIGH","integrityImpact":"NONE","availabilityImpact":"HIGH"}},{"version":"3.1","source":"CNA","type":"DECLARED","score":"7.1","severity":"HIGH","vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H","data":{"baseScore":7.1,"baseSeverity":"HIGH","vectorString":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H","version":"3.1"}}],"references":[{"url":"https://git.kernel.org/stable/c/bbae351c0f32f7c200249e4aa6561b2b419dcf69","name":"https://git.kernel.org/stable/c/bbae351c0f32f7c200249e4aa6561b2b419dcf69","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/782708ca1ea1f68b8cbb5ea3a7f5f18d0000efae","name":"https://git.kernel.org/stable/c/782708ca1ea1f68b8cbb5ea3a7f5f18d0000efae","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/27ddf4486c7dbf5bdd393fa8bef6b67179796d98","name":"https://git.kernel.org/stable/c/27ddf4486c7dbf5bdd393fa8bef6b67179796d98","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/a094ac95d3b69adfa1676eb9c8eae6835d4f1671","name":"https://git.kernel.org/stable/c/a094ac95d3b69adfa1676eb9c8eae6835d4f1671","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/efb8763d7bbb40cff4cc55a6b62c3095a038149c","name":"https://git.kernel.org/stable/c/efb8763d7bbb40cff4cc55a6b62c3095a038149c","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/99206ce2244f8a3ed64298d0667c9055845a5dc7","name":"https://git.kernel.org/stable/c/99206ce2244f8a3ed64298d0667c9055845a5dc7","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/e81f805824a8109504fce090641b17d135b48cd1","name":"https://git.kernel.org/stable/c/e81f805824a8109504fce090641b17d135b48cd1","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/f0d88a4cd03affff6c08adf6c63964e235aede43","name":"https://git.kernel.org/stable/c/f0d88a4cd03affff6c08adf6c63964e235aede43","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://www.cve.org/CVERecord?id=CVE-2026-64422","name":"CVE Program record","refsource":"CVE.ORG","tags":["canonical"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-64422","name":"NVD vulnerability detail","refsource":"NVD","tags":["canonical","analysis"]}],"affected":[{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 91cc17c0e5e5ada156a8d5787a2509d263ea6bbf f0d88a4cd03affff6c08adf6c63964e235aede43 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 91cc17c0e5e5ada156a8d5787a2509d263ea6bbf 27ddf4486c7dbf5bdd393fa8bef6b67179796d98 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 91cc17c0e5e5ada156a8d5787a2509d263ea6bbf 782708ca1ea1f68b8cbb5ea3a7f5f18d0000efae git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 91cc17c0e5e5ada156a8d5787a2509d263ea6bbf e81f805824a8109504fce090641b17d135b48cd1 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 91cc17c0e5e5ada156a8d5787a2509d263ea6bbf 99206ce2244f8a3ed64298d0667c9055845a5dc7 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 91cc17c0e5e5ada156a8d5787a2509d263ea6bbf bbae351c0f32f7c200249e4aa6561b2b419dcf69 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 91cc17c0e5e5ada156a8d5787a2509d263ea6bbf a094ac95d3b69adfa1676eb9c8eae6835d4f1671 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 91cc17c0e5e5ada156a8d5787a2509d263ea6bbf efb8763d7bbb40cff4cc55a6b62c3095a038149c git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 2.6.24","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 2.6.24 semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 5.10.261 5.10.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 5.15.212 5.15.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 6.1.178 6.1.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 6.6.145 6.6.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 6.12.96 6.12.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 6.18.39 6.18.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 7.1.4 7.1.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 7.2-rc1 * original_commit_for_fix","platforms":[]}],"timeline":[],"solutions":[],"workarounds":[],"exploits":[],"credits":[],"nvd_cpes":[],"vendor_comments":[],"enrichments":{"kev":null,"epss":{"cve_year":"2026","cve_id":"64422","cve":"CVE-2026-64422","epss":"0.001320000","percentile":"0.031450000","score_date":"2026-07-27","updated_at":"2026-07-28 00:07:43"},"legacy_qids":[]},"source_records":{"cve_program":{"containers":{"cna":{"affected":[{"defaultStatus":"unaffected","product":"Linux","programFiles":["net/ipv4/sysctl_net_ipv4.c","net/ipv4/tcp_output.c"],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","vendor":"Linux","versions":[{"lessThan":"f0d88a4cd03affff6c08adf6c63964e235aede43","status":"affected","version":"91cc17c0e5e5ada156a8d5787a2509d263ea6bbf","versionType":"git"},{"lessThan":"27ddf4486c7dbf5bdd393fa8bef6b67179796d98","status":"affected","version":"91cc17c0e5e5ada156a8d5787a2509d263ea6bbf","versionType":"git"},{"lessThan":"782708ca1ea1f68b8cbb5ea3a7f5f18d0000efae","status":"affected","version":"91cc17c0e5e5ada156a8d5787a2509d263ea6bbf","versionType":"git"},{"lessThan":"e81f805824a8109504fce090641b17d135b48cd1","status":"affected","version":"91cc17c0e5e5ada156a8d5787a2509d263ea6bbf","versionType":"git"},{"lessThan":"99206ce2244f8a3ed64298d0667c9055845a5dc7","status":"affected","version":"91cc17c0e5e5ada156a8d5787a2509d263ea6bbf","versionType":"git"},{"lessThan":"bbae351c0f32f7c200249e4aa6561b2b419dcf69","status":"affected","version":"91cc17c0e5e5ada156a8d5787a2509d263ea6bbf","versionType":"git"},{"lessThan":"a094ac95d3b69adfa1676eb9c8eae6835d4f1671","status":"affected","version":"91cc17c0e5e5ada156a8d5787a2509d263ea6bbf","versionType":"git"},{"lessThan":"efb8763d7bbb40cff4cc55a6b62c3095a038149c","status":"affected","version":"91cc17c0e5e5ada156a8d5787a2509d263ea6bbf","versionType":"git"}]},{"defaultStatus":"affected","product":"Linux","programFiles":["net/ipv4/sysctl_net_ipv4.c","net/ipv4/tcp_output.c"],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","vendor":"Linux","versions":[{"status":"affected","version":"2.6.24"},{"lessThan":"2.6.24","status":"unaffected","version":"0","versionType":"semver"},{"lessThanOrEqual":"5.10.*","status":"unaffected","version":"5.10.261","versionType":"semver"},{"lessThanOrEqual":"5.15.*","status":"unaffected","version":"5.15.212","versionType":"semver"},{"lessThanOrEqual":"6.1.*","status":"unaffected","version":"6.1.178","versionType":"semver"},{"lessThanOrEqual":"6.6.*","status":"unaffected","version":"6.6.145","versionType":"semver"},{"lessThanOrEqual":"6.12.*","status":"unaffected","version":"6.12.96","versionType":"semver"},{"lessThanOrEqual":"6.18.*","status":"unaffected","version":"6.18.39","versionType":"semver"},{"lessThanOrEqual":"7.1.*","status":"unaffected","version":"7.1.4","versionType":"semver"},{"lessThanOrEqual":"*","status":"unaffected","version":"7.2-rc1","versionType":"original_commit_for_fix"}]}],"cpeApplicability":[{"nodes":[{"cpeMatch":[{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"5.10.261","versionStartIncluding":"2.6.24","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"5.15.212","versionStartIncluding":"2.6.24","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"6.1.178","versionStartIncluding":"2.6.24","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"6.6.145","versionStartIncluding":"2.6.24","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"6.12.96","versionStartIncluding":"2.6.24","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"6.18.39","versionStartIncluding":"2.6.24","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"7.1.4","versionStartIncluding":"2.6.24","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"7.2-rc1","versionStartIncluding":"2.6.24","vulnerable":true}],"negate":false,"operator":"OR"}]}],"descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\nnet: ipv4: bound TCP reordering sysctl writes and MTU probe sizes\n\nReject invalid `net.ipv4.tcp_reordering` values before they reach TCP\nsocket state. The sysctl is stored as an `int` but copied into the\n`u32` `tp->reordering` field for new sockets, so negative writes wrap\nto large values.\n\nWith `tcp_mtu_probing=2`, the wrapped value can overflow the\n`tcp_mtu_probe()` size calculation and drive the MTU probing path into\nan out-of-bounds read. Route `tcp_reordering` writes through\n`proc_dointvec_minmax()` and require it to be at least 1. Also require\n`tcp_max_reordering` to be at least 1 so the configured maximum cannot\nbecome negative either.\n\nWhen registering the table for a non-init network namespace, relocate\n`extra2` pointers that refer into `init_net.ipv4` so the\n`tcp_reordering` upper bound follows that namespace's\n`tcp_max_reordering`.\n\nHarden `tcp_mtu_probe()` itself by computing `size_needed` as `u64`.\nThis keeps the send queue and window checks from being bypassed through\nsigned integer overflow."}],"metrics":[{"cvssV3_1":{"baseScore":7.1,"baseSeverity":"HIGH","vectorString":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H","version":"3.1"}}],"providerMetadata":{"dateUpdated":"2026-07-27T05:00:48.900Z","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","shortName":"Linux"},"references":[{"url":"https://git.kernel.org/stable/c/f0d88a4cd03affff6c08adf6c63964e235aede43"},{"url":"https://git.kernel.org/stable/c/27ddf4486c7dbf5bdd393fa8bef6b67179796d98"},{"url":"https://git.kernel.org/stable/c/782708ca1ea1f68b8cbb5ea3a7f5f18d0000efae"},{"url":"https://git.kernel.org/stable/c/e81f805824a8109504fce090641b17d135b48cd1"},{"url":"https://git.kernel.org/stable/c/99206ce2244f8a3ed64298d0667c9055845a5dc7"},{"url":"https://git.kernel.org/stable/c/bbae351c0f32f7c200249e4aa6561b2b419dcf69"},{"url":"https://git.kernel.org/stable/c/a094ac95d3b69adfa1676eb9c8eae6835d4f1671"},{"url":"https://git.kernel.org/stable/c/efb8763d7bbb40cff4cc55a6b62c3095a038149c"}],"title":"net: ipv4: bound TCP reordering sysctl writes and MTU probe sizes","x_generator":{"engine":"bippy-1.2.0"}}},"cveMetadata":{"assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","assignerShortName":"Linux","cveId":"CVE-2026-64422","datePublished":"2026-07-25T08:51:00.671Z","dateReserved":"2026-07-19T15:36:31.787Z","dateUpdated":"2026-07-27T05:00:48.900Z","state":"PUBLISHED"},"dataType":"CVE_RECORD","dataVersion":"5.2"},"nvd":{"publishedDate":"2026-07-25 10:17:26","lastModifiedDate":"2026-07-27 05:16:48","problem_types":[],"metrics":{"cvssMetricV31":[{"source":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","type":"Secondary","cvssData":{"version":"3.1","vectorString":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H","baseScore":7.1,"baseSeverity":"HIGH","attackVector":"LOCAL","attackComplexity":"LOW","privilegesRequired":"LOW","userInteraction":"NONE","scope":"UNCHANGED","confidentialityImpact":"HIGH","integrityImpact":"NONE","availabilityImpact":"HIGH"},"exploitabilityScore":1.8,"impactScore":5.2}]},"configurations":[]},"legacy_mitre":{"record":{"CveYear":"2026","CveId":"64422","Ordinal":"1","Title":"net: ipv4: bound TCP reordering sysctl writes and MTU probe size","CVE":"CVE-2026-64422","Year":"2026"},"notes":[{"CveYear":"2026","CveId":"64422","Ordinal":"1","NoteData":"In the Linux kernel, the following vulnerability has been resolved:\n\nnet: ipv4: bound TCP reordering sysctl writes and MTU probe sizes\n\nReject invalid `net.ipv4.tcp_reordering` values before they reach TCP\nsocket state. The sysctl is stored as an `int` but copied into the\n`u32` `tp->reordering` field for new sockets, so negative writes wrap\nto large values.\n\nWith `tcp_mtu_probing=2`, the wrapped value can overflow the\n`tcp_mtu_probe()` size calculation and drive the MTU probing path into\nan out-of-bounds read. Route `tcp_reordering` writes through\n`proc_dointvec_minmax()` and require it to be at least 1. Also require\n`tcp_max_reordering` to be at least 1 so the configured maximum cannot\nbecome negative either.\n\nWhen registering the table for a non-init network namespace, relocate\n`extra2` pointers that refer into `init_net.ipv4` so the\n`tcp_reordering` upper bound follows that namespace's\n`tcp_max_reordering`.\n\nHarden `tcp_mtu_probe()` itself by computing `size_needed` as `u64`.\nThis keeps the send queue and window checks from being bypassed through\nsigned integer overflow.","Type":"Description","Title":"net: ipv4: bound TCP reordering sysctl writes and MTU probe size"}]}}}