{"id":"CVE-2026-63867","revision":"9c587df57e8149c1a67911545fb997a3","records":[{"revision":"9c587df57e8149c1a67911545fb997a3","observedAt":"2026-10-23T15:48:27.903+00:00","statement":{"source":"cve-program","id":"CVE-2026-63867","aliases":[],"title":"mptcp: close TOCTOU race while computing rcv_wnd","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nmptcp: close TOCTOU race while computing rcv_wnd\n\nThe MPTCP output path access locklessly the MPTCP-level ack_seq\nin multiple times, using possibly different values for the data_ack\nin the DSS option and to compute the announced rcv wnd for the same\npacket.\n\nRefactor the cote to avoid inconsistencies which may confuse the\npeer. Also ensure that the MPTCP level rcv wnd is updated only when\nthe egress packet actually contains a DSS ack.","state":0,"publishedAt":"2026-07-19T14:18:37.234+00:00","modifiedAt":"2026-10-19T20:17:53.288+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/mptcp/options.c\"\n                    ],\n                    \"versions\": [\n                        {\n                            \"version\": \"fa3fe2b150316b294f2c662653501273ff25bba8\",\n                            \"lessThan\": \"301a33fd590c408a05c5df800e0cc1e6a8a2f8f8\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        },\n                        {\n                            \"version\": \"fa3fe2b150316b294f2c662653501273ff25bba8\",\n                            \"lessThan\": \"68364963e5baf03f16b4420292291f75c8f66497\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        },\n                        {\n                            \"version\": \"fa3fe2b150316b294f2c662653501273ff25bba8\",\n                            \"lessThan\": \"907ac6b1658e0277f979fcdfae2a753b495c1510\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        },\n                        {\n                            \"version\": \"fa3fe2b150316b294f2c662653501273ff25bba8\",\n                            \"lessThan\": \"c4f4cf60797974873dbc8e100144682a6f2f861f\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        },\n                        {\n                            \"version\": \"fa3fe2b150316b294f2c662653501273ff25bba8\",\n                            \"lessThan\": \"3b8cbba7c0ed31189c89f90be247b8973ffa79ef\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        },\n                        {\n                            \"version\": \"fa3fe2b150316b294f2c662653501273ff25bba8\",\n                            \"lessThan\": \"8f4f0a157e8436a05bf8c3670b24dbc258911c43\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        },\n                        {\n                            \"version\": \"fa3fe2b150316b294f2c662653501273ff25bba8\",\n                            \"lessThan\": \"8ab24fdebc369c0dfb90f82c1650b1e66662bb45\",\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/mptcp/options.c\"\n                    ],\n                    \"versions\": [\n                        {\n                            \"version\": \"5.11\",\n                            \"status\": \"affected\"\n                        },\n                        {\n                            \"version\": \"0\",\n                            \"lessThan\": \"5.11\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"5.15.210\",\n                            \"lessThanOrEqual\": \"5.15.*\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"6.1.176\",\n                            \"lessThanOrEqual\": \"6.1.*\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"6.6.143\",\n                            \"lessThanOrEqual\": \"6.6.*\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"6.12.94\",\n                            \"lessThanOrEqual\": \"6.12.*\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"6.18.36\",\n                            \"lessThanOrEqual\": \"6.18.*\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"7.0.13\",\n                            \"lessThanOrEqual\": \"7.0.*\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"7.1\",\n                            \"lessThanOrEqual\": \"*\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"original_commit_for_fix\"\n                        }\n                    ]\n                }"}],"metrics":[{"system":"CVSS 3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:H","score":8.2,"severity":"HIGH"}],"references":["https://git.kernel.org/stable/c/301a33fd590c408a05c5df800e0cc1e6a8a2f8f8","https://git.kernel.org/stable/c/68364963e5baf03f16b4420292291f75c8f66497","https://git.kernel.org/stable/c/907ac6b1658e0277f979fcdfae2a753b495c1510","https://git.kernel.org/stable/c/c4f4cf60797974873dbc8e100144682a6f2f861f","https://git.kernel.org/stable/c/3b8cbba7c0ed31189c89f90be247b8973ffa79ef","https://git.kernel.org/stable/c/8f4f0a157e8436a05bf8c3670b24dbc258911c43","https://git.kernel.org/stable/c/8ab24fdebc369c0dfb90f82c1650b1e66662bb45"],"sourceUrl":"https://www.cve.org/CVERecord?id=CVE-2026-63867","license":"CVE Program Terms of Use","key":"cve-program:CVE-2026-63867","identifiers":["CVE-2026-63867"]},"retained":false,"historicalAffected":[]}],"coverage":[]}