{"id":"CVE-2026-64564","published":"2026-08-04T07:16:31.340","lastModified":"2026-08-09T04:17:43.283","description":"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->transport (== chunk->transport, 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->transport.\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->transport still\npoints at, freeing it (RCU-deferred). The following wildcard DEL-IP then\nreuses the now-dangling asconf->transport in sctp_assoc_set_primary() and\nsctp_assoc_del_nonprimary_peers(): set_primary() dereferences the freed\ntransport (->ipaddr, ->state) and plants the dangling pointer into\nasoc->peer.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.","cvssScore":9.8,"cvssSeverity":"CRITICAL","cvssVector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H","cwes":[],"vendors":[],"products":[],"references":[{"url":"https://git.kernel.org/stable/c/74e8f3e7114f0e26d1b2c4c048044db9fcc27603","tags":[]},{"url":"https://git.kernel.org/stable/c/85aca407c560aba81b5ce9d3d6cf94c74077d19b","tags":[]},{"url":"https://git.kernel.org/stable/c/9b2854f86f0b56e9027d68e7a3fc909d1a9b566f","tags":[]},{"url":"https://git.kernel.org/stable/c/d136b29bf91dd8e3161281b87de597b7311d9462","tags":[]},{"url":"https://git.kernel.org/stable/c/fedeb4468987bcaff85fe3061de5ae052d414740","tags":[]},{"url":"https://matrix.tencent.com/en/2026/08/06/sctphantom-CVE-2026-64564","tags":[]},{"url":"http://www.openwall.com/lists/oss-security/2026/08/06/13","tags":[]},{"url":"http://www.openwall.com/lists/oss-security/2026/08/06/3","tags":[]},{"url":"http://www.openwall.com/lists/oss-security/2026/08/06/4","tags":[]},{"url":"http://www.openwall.com/lists/oss-security/2026/08/07/1","tags":[]},{"url":"http://www.openwall.com/lists/oss-security/2026/08/07/2","tags":[]},{"url":"http://www.openwall.com/lists/oss-security/2026/08/07/8","tags":[]}],"exploitRefs":[],"hasPoc":false,"ai":{"summary":"This vulnerability allows an attacker to free a transport structure and then reuse it, leading to potential denial of service or other critical issues in SCTP associations.","exploitability":"Exploitation requires specific ASCONF chunk sequences and could be moderately difficult due to the need for precise control over packet contents.","blast_radius":"If exploited, this vulnerability could lead to a complete loss of association integrity, impacting network services relying on SCTP.","remediation":"Update to the latest kernel version that addresses this issue.","tags":["sctp","kernel","dos","critical"],"model":"qwen2.5:7b-instruct","analyzedAt":"2026-08-11T06:41:15.634Z"}}