{"id":"AZL-100725","summary":"CVE-2026-89554 affecting package kernel 6.6.150.1-1","details":"In the Linux kernel, the following vulnerability has been resolved:\n\nmptcp: fix uninitialized local_id in syncookie MP_JOIN reconstruction\n\nmptcp_token_join_cookie_init_state() restores remote_nonce, local_nonce,\nbackup, join_id, token and msk from the saved cookie entry when rebuilding\nthe request socket for a MP_JOIN 4th-ACK handled under SYN cookies, but it\ndoes not restore local_id, even though the SYN path saved it.\nsubflow_ulp_clone() then reads that uninitialized field and stores it as\nthe joined subflow's address-ID. Because the request-sock slab is\nSLAB_TYPESAFE_BY_RCU and not zeroed on allocation, the value is the stale\nbyte of a previously freed request socket, which an off-path peer can\ninfluence by sending concurrent MP_JOIN SYNs. This corrupts the path\nmanager's id-based subflow bookkeeping for the connection.\n\nRestore subflow_req-\u003elocal_id from the cookie entry, as done for the other\nfields.","modified":"2026-09-12T14:15:31.276683875Z","published":"2026-09-11T20:19:39Z","upstream":["CVE-2026-89554"],"references":[{"type":"WEB","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-89554"}],"affected":[{"package":{"name":"kernel","ecosystem":"Azure Linux:3","purl":"pkg:rpm/azure-linux/kernel"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"last_affected":"6.6.150.1-1"}]}],"database_specific":{"source":"https://github.com/microsoft/AzureLinuxVulnerabilityData/blob/main/osv/AZL-100725.json"}}],"schema_version":"1.9.0"}