{"id":"CVE-2026-74587","aliases":[],"url":"https://o3.security/vulnerability/CVE-2026-74587","summary":"sctp: fix use-after-free of cached ASCONF chunk","details":"In the Linux kernel, the following vulnerability has been resolved:\n\nsctp: fix use-after-free of cached ASCONF chunk\n\naddip_last_asconf caches the outstanding outbound ASCONF chunk. The normal\nASCONF-ACK completion path releases the chunk and clears the pointer.\n\nHowever, sctp_asconf_queue_teardown() releases the cached chunk without\nclearing addip_last_asconf. During peer restart handling,\nsctp_sf_do_dupcook_a() queues SCTP_CMD_PURGE_ASCONF_QUEUE, which invokes\nsctp_asconf_queue_teardown() while the association remains alive and leaves\nthe pointer dangling.\n\nA delayed authenticated ASCONF-ACK can then reach sctp_sf_do_asconf_ack(),\nwhich accesses the stale chunk and passes it to sctp_process_asconf_ack(),\ncausing a use-after-free and a second release.\n\nClearing the pointer exposes a race with T4 expiry. Peer restart handling\nqueues the timer stop before the purge, but SCTP_CMD_TIMER_STOP uses\ntimer_delete(), which does not wait for a callback already running on\nanother CPU. Such a callback can reach sctp_sf_t4_timer_expire() after\nthe purge and dereference NULL.\n\nClear addip_last_asconf after releasing the cached chunk, and make\nsctp_sf_t4_timer_expire() consume a stale T4 expiry if no outstanding\nASCONF remains.","published":"2026-08-22T15:31:39.810Z","modified":"2026-08-24T11:47:06.483390401Z","cvss":null,"epss":null,"cisaKev":null,"exploitsKnown":null,"affectedPackages":[{"ecosystem":"Linux","name":"Kernel","fixedVersion":"5.10.265"}],"fix":null,"references":[{"type":"WEB","url":"https://git.kernel.org/stable/c/07daf4f9750104960a1d60831b2353c0d41f35fb"},{"type":"WEB","url":"https://git.kernel.org/stable/c/10459b03e2d9ee12435e96f587de4d4cacdbf435"},{"type":"WEB","url":"https://git.kernel.org/stable/c/179676f0166230c80053a392303485b37c93dd33"},{"type":"WEB","url":"https://git.kernel.org/stable/c/618b5c6d049896fcfabb91afc072954c92cb2693"},{"type":"WEB","url":"https://git.kernel.org/stable/c/8c283e7b56adce00193837f3311b06662466fb21"},{"type":"WEB","url":"https://git.kernel.org/stable/c/d949992bc3f00027a2c755e860a11950c75f6073"},{"type":"WEB","url":"https://git.kernel.org/stable/c/dc67d528c2fa939cec7fe3bf7f3089c8d281ca3d"},{"type":"WEB","url":"https://git.kernel.org/stable/c/e1bb114e09372fd6e03387ced9ef566da336ed6c"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/74xxx/CVE-2026-74587.json"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-74587"},{"type":"PACKAGE","url":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git"}],"provenance":{"sources":["OSV.dev","FIRST.org (EPSS)"],"lastVerified":"2026-08-24T11:47:06.483390401Z"}}