{"id":"AZL-94395","summary":"CVE-2026-64564 affecting package kernel for versions less than 6.6.150.1-1","details":"In the Linux kernel, the following vulnerability has been resolved:\n\nsctp: don't free the ASCONF's own transport in DEL-IP processing\n\nsctp_process_asconf() caches the transport the ASCONF chunk is processed\nagainst in asconf-\u003etransport (== chunk-\u003etransport, set once in sctp_rcv()).\nFor an ASCONF located through its Address Parameter by\n__sctp_rcv_asconf_lookup(), that cached transport corresponds to the\nAddress Parameter, which need not be the packet's source address.\n\nsctp_process_asconf_param() rejects a DEL-IP for the packet source address\n(ADDIP D8, SCTP_ERROR_DEL_SRC_IP), but nothing protects asconf-\u003etransport.\nA single ASCONF can therefore carry, in order:\n\n    [Address Parameter L] [DEL-IP L] [DEL-IP 0.0.0.0]\n\nwhere L differs from the source. The DEL-IP for L passes the D8 check and\ncalls sctp_assoc_rm_peer() on the transport that asconf-\u003etransport still\npoints at, freeing it (RCU-deferred). The following wildcard DEL-IP then\nreuses the now-dangling asconf-\u003etransport in sctp_assoc_set_primary() and\nsctp_assoc_del_nonprimary_peers(): set_primary() dereferences the freed\ntransport (-\u003eipaddr, -\u003estate) and plants the dangling pointer into\nasoc-\u003epeer.primary_path / active_path, and del_nonprimary_peers(), keeping\nonly the pointer that is no longer on the list, removes every real\ntransport, leaving the association with a transport_count of 0 and\nprimary_path/active_path pointing at freed memory.\n\nReject a DEL-IP that targets the transport the ASCONF is being processed\nagainst, mirroring the existing source-address guard, so the wildcard\nbranch can never reuse a freed transport.","modified":"2026-08-28T17:47:44.912369042Z","published":"2026-08-04T07:16:31Z","upstream":["CVE-2026-64564"],"references":[{"type":"WEB","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-64564"}],"affected":[{"package":{"name":"kernel","ecosystem":"Azure Linux:3","purl":"pkg:rpm/azure-linux/kernel"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"6.6.150.1-1"}]}],"database_specific":{"source":"https://github.com/microsoft/AzureLinuxVulnerabilityData/blob/main/osv/AZL-94395.json"}}],"schema_version":"1.9.0"}