{"api_version":"1","generated_at":"2026-07-23T14:27:40+00:00","cve":"CVE-2026-45889","urls":{"html":"https://cve.report/CVE-2026-45889","api":"https://cve.report/api/cve/CVE-2026-45889.json","docs":"https://cve.report/api","cve_org":"https://www.cve.org/CVERecord?id=CVE-2026-45889","nvd":"https://nvd.nist.gov/vuln/detail/CVE-2026-45889"},"summary":{"title":"mptcp: do not account for OoO in mptcp_rcvbuf_grow()","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nmptcp: do not account for OoO in mptcp_rcvbuf_grow()\n\nMPTCP-level OoOs are physiological when multiple subflows are active\nconcurrently and will not cause retransmissions nor are caused by\ndrops.\n\nAccounting for them in mptcp_rcvbuf_grow() causes the rcvbuf slowly\ndrifting towards tcp_rmem[2].\n\nRemove such accounting. Note that subflows will still account for TCP-level\nOoO when the MPTCP-level rcvbuf is propagated.\n\nThis also closes a subtle and very unlikely race condition with rcvspace\ninit; active sockets with user-space holding the msk-level socket lock,\ncould complete such initialization in the receive callback, after that the\nfirst OoO data reaches the rcvbuf and potentially triggering a divide by\nzero Oops.","state":"PUBLISHED","assigner":"Linux","published_at":"2026-05-27 14:17:02","updated_at":"2026-06-25 21:11:20"},"problem_types":["CWE-369"],"metrics":[{"version":"3.1","source":"nvd@nist.gov","type":"Primary","score":"5.5","severity":"MEDIUM","vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H","data":{"version":"3.1","vectorString":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H","baseScore":5.5,"baseSeverity":"MEDIUM","attackVector":"LOCAL","attackComplexity":"LOW","privilegesRequired":"LOW","userInteraction":"NONE","scope":"UNCHANGED","confidentialityImpact":"NONE","integrityImpact":"NONE","availabilityImpact":"HIGH"}}],"references":[{"url":"https://git.kernel.org/stable/c/6b329393502e5857662b851a13f947209c588587","name":"https://git.kernel.org/stable/c/6b329393502e5857662b851a13f947209c588587","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":["Patch"],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/fb7bf00b04a6b48859f52035d4e745848c2b4c79","name":"https://git.kernel.org/stable/c/fb7bf00b04a6b48859f52035d4e745848c2b4c79","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":["Patch"],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/400ee4854adef1e4983812a3decf6717ea020136","name":"https://git.kernel.org/stable/c/400ee4854adef1e4983812a3decf6717ea020136","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":["Patch"],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://www.cve.org/CVERecord?id=CVE-2026-45889","name":"CVE 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the Linux kernel, the following vulnerability has been resolved:\n\nmptcp: do not account for OoO in mptcp_rcvbuf_grow()\n\nMPTCP-level OoOs are physiological when multiple subflows are active\nconcurrently and will not cause retransmissions nor are caused by\ndrops.\n\nAccounting for them in mptcp_rcvbuf_grow() causes the rcvbuf slowly\ndrifting towards tcp_rmem[2].\n\nRemove such accounting. Note that subflows will still account for TCP-level\nOoO when the MPTCP-level rcvbuf is propagated.\n\nThis also closes a subtle and very unlikely race condition with rcvspace\ninit; active sockets with user-space holding the msk-level socket lock,\ncould complete such initialization in the receive callback, after that the\nfirst OoO data reaches the rcvbuf and potentially triggering a divide by\nzero Oops."}],"providerMetadata":{"dateUpdated":"2026-05-27T12:17:00.509Z","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","shortName":"Linux"},"references":[{"url":"https://git.kernel.org/stable/c/fb7bf00b04a6b48859f52035d4e745848c2b4c79"},{"url":"https://git.kernel.org/stable/c/400ee4854adef1e4983812a3decf6717ea020136"},{"url":"https://git.kernel.org/stable/c/6b329393502e5857662b851a13f947209c588587"}],"title":"mptcp: do not account for OoO in mptcp_rcvbuf_grow()","x_generator":{"engine":"bippy-1.2.0"}}},"cveMetadata":{"assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","assignerShortName":"Linux","cveId":"CVE-2026-45889","datePublished":"2026-05-27T12:17:00.509Z","dateReserved":"2026-05-13T15:03:33.082Z","dateUpdated":"2026-05-27T12:17:00.509Z","state":"PUBLISHED"},"dataType":"CVE_RECORD","dataVersion":"5.2"},"nvd":{"publishedDate":"2026-05-27 14:17:02","lastModifiedDate":"2026-06-25 21:11:20","problem_types":["CWE-369"],"metrics":{"cvssMetricV31":[{"source":"nvd@nist.gov","type":"Primary","cvssData":{"version":"3.1","vectorString":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H","baseScore":5.5,"baseSeverity":"MEDIUM","attackVector":"LOCAL","attackComplexity":"LOW","privilegesRequired":"LOW","userInteraction":"NONE","scope":"UNCHANGED","confidentialityImpact":"NONE","integrityImpact":"NONE","availabilityImpact":"HIGH"},"exploitabilityScore":1.8,"impactScore":3.6}]},"configurations":[{"nodes":[{"operator":"OR","negate":false,"cpeMatch":[{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.18","versionEndExcluding":"6.18.14","matchCriteriaId":"3E0E101B-8972-4E77-80E0-D97AC3CA57C1"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.19","versionEndExcluding":"6.19.4","matchCriteriaId":"672A3E79-EC03-479D-8503-361DFBDC8092"}]}]}]},"legacy_mitre":{"record":{"CveYear":"2026","CveId":"45889","Ordinal":"1","Title":"mptcp: do not account for OoO in mptcp_rcvbuf_grow()","CVE":"CVE-2026-45889","Year":"2026"},"notes":[{"CveYear":"2026","CveId":"45889","Ordinal":"1","NoteData":"In the Linux kernel, the following vulnerability has been resolved:\n\nmptcp: do not account for OoO in mptcp_rcvbuf_grow()\n\nMPTCP-level OoOs are physiological when multiple subflows are active\nconcurrently and will not cause retransmissions nor are caused by\ndrops.\n\nAccounting for them in mptcp_rcvbuf_grow() causes the rcvbuf slowly\ndrifting towards tcp_rmem[2].\n\nRemove such accounting. Note that subflows will still account for TCP-level\nOoO when the MPTCP-level rcvbuf is propagated.\n\nThis also closes a subtle and very unlikely race condition with rcvspace\ninit; active sockets with user-space holding the msk-level socket lock,\ncould complete such initialization in the receive callback, after that the\nfirst OoO data reaches the rcvbuf and potentially triggering a divide by\nzero Oops.","Type":"Description","Title":"mptcp: do not account for OoO in mptcp_rcvbuf_grow()"}]}}}