{"id":"CVE-2026-64422","revision":"741e5dfae8c24c98b6513cc1cedc9757","records":[{"revision":"741e5dfae8c24c98b6513cc1cedc9757","observedAt":"2026-10-23T15:48:27.903+00:00","statement":{"source":"cve-program","id":"CVE-2026-64422","aliases":[],"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":0,"publishedAt":"2026-07-25T08:51:00.671+00:00","modifiedAt":"2026-10-19T20:38:28.132+00:00","affected":[{"ecosystem":"Vendor product","name":"Linux","ranges":[],"versions":[],"rawVersionEvidence":"{\n                    \"product\": \"Linux\",\n                    \"vendor\": \"Linux\",\n                    \"defaultStatus\": \"unaffected\",\n                    \"repo\": \"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git\",\n                    \"programFiles\": [\n                        \"net/ipv4/sysctl_net_ipv4.c\",\n                        \"net/ipv4/tcp_output.c\"\n                    ],\n                    \"versions\": [\n                        {\n                            \"version\": \"91cc17c0e5e5ada156a8d5787a2509d263ea6bbf\",\n                            \"lessThan\": \"f0d88a4cd03affff6c08adf6c63964e235aede43\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        },\n                        {\n                            \"version\": \"91cc17c0e5e5ada156a8d5787a2509d263ea6bbf\",\n                            \"lessThan\": \"27ddf4486c7dbf5bdd393fa8bef6b67179796d98\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        },\n                        {\n                            \"version\": \"91cc17c0e5e5ada156a8d5787a2509d263ea6bbf\",\n                            \"lessThan\": \"782708ca1ea1f68b8cbb5ea3a7f5f18d0000efae\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        },\n                        {\n                            \"version\": \"91cc17c0e5e5ada156a8d5787a2509d263ea6bbf\",\n                            \"lessThan\": \"e81f805824a8109504fce090641b17d135b48cd1\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        },\n                        {\n                            \"version\": \"91cc17c0e5e5ada156a8d5787a2509d263ea6bbf\",\n                            \"lessThan\": \"99206ce2244f8a3ed64298d0667c9055845a5dc7\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        },\n                        {\n                            \"version\": \"91cc17c0e5e5ada156a8d5787a2509d263ea6bbf\",\n                            \"lessThan\": \"bbae351c0f32f7c200249e4aa6561b2b419dcf69\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        },\n                        {\n                            \"version\": \"91cc17c0e5e5ada156a8d5787a2509d263ea6bbf\",\n                            \"lessThan\": \"a094ac95d3b69adfa1676eb9c8eae6835d4f1671\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        },\n                        {\n                            \"version\": \"91cc17c0e5e5ada156a8d5787a2509d263ea6bbf\",\n                            \"lessThan\": \"efb8763d7bbb40cff4cc55a6b62c3095a038149c\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        }\n                    ]\n                }"},{"ecosystem":"Vendor product","name":"Linux","ranges":[],"versions":[],"rawVersionEvidence":"{\n                    \"product\": \"Linux\",\n                    \"vendor\": \"Linux\",\n                    \"defaultStatus\": \"affected\",\n                    \"repo\": \"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git\",\n                    \"programFiles\": [\n                        \"net/ipv4/sysctl_net_ipv4.c\",\n                        \"net/ipv4/tcp_output.c\"\n                    ],\n                    \"versions\": [\n                        {\n                            \"version\": \"2.6.24\",\n                            \"status\": \"affected\"\n                        },\n                        {\n                            \"version\": \"0\",\n                            \"lessThan\": \"2.6.24\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"5.10.261\",\n                            \"lessThanOrEqual\": \"5.10.*\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"5.15.212\",\n                            \"lessThanOrEqual\": \"5.15.*\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"6.1.178\",\n                            \"lessThanOrEqual\": \"6.1.*\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"6.6.145\",\n                            \"lessThanOrEqual\": \"6.6.*\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"6.12.96\",\n                            \"lessThanOrEqual\": \"6.12.*\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"6.18.39\",\n                            \"lessThanOrEqual\": \"6.18.*\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"7.1.4\",\n                            \"lessThanOrEqual\": \"7.1.*\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"7.2\",\n                            \"lessThanOrEqual\": \"*\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"original_commit_for_fix\"\n                        }\n                    ]\n                }"}],"metrics":[{"system":"CVSS 3.1","vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H","score":7.1,"severity":"HIGH"}],"references":["https://git.kernel.org/stable/c/f0d88a4cd03affff6c08adf6c63964e235aede43","https://git.kernel.org/stable/c/27ddf4486c7dbf5bdd393fa8bef6b67179796d98","https://git.kernel.org/stable/c/782708ca1ea1f68b8cbb5ea3a7f5f18d0000efae","https://git.kernel.org/stable/c/e81f805824a8109504fce090641b17d135b48cd1","https://git.kernel.org/stable/c/99206ce2244f8a3ed64298d0667c9055845a5dc7","https://git.kernel.org/stable/c/bbae351c0f32f7c200249e4aa6561b2b419dcf69","https://git.kernel.org/stable/c/a094ac95d3b69adfa1676eb9c8eae6835d4f1671","https://git.kernel.org/stable/c/efb8763d7bbb40cff4cc55a6b62c3095a038149c"],"sourceUrl":"https://www.cve.org/CVERecord?id=CVE-2026-64422","license":"CVE Program Terms of Use","key":"cve-program:CVE-2026-64422","identifiers":["CVE-2026-64422"]},"retained":false,"historicalAffected":[]}],"coverage":[]}