{"id":"CVE-2026-74587","title":"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","summary":"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 chun…","severity":"critical","cvss":9.8,"cvssVector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H","vendor":"Linux","product":"Linux","affected":["Linux >= a000c01e60e40e15304ffe48fff051d17a7bea91 < 10459b03e2d9ee12435e96f587de4d4cacdbf435","Linux >= a000c01e60e40e15304ffe48fff051d17a7bea91 < e1bb114e09372fd6e03387ced9ef566da336ed6c","Linux >= a000c01e60e40e15304ffe48fff051d17a7bea91 < 179676f0166230c80053a392303485b37c93dd33","Linux >= a000c01e60e40e15304ffe48fff051d17a7bea91 < dc67d528c2fa939cec7fe3bf7f3089c8d281ca3d","Linux >= a000c01e60e40e15304ffe48fff051d17a7bea91 < 618b5c6d049896fcfabb91afc072954c92cb2693","Linux >= a000c01e60e40e15304ffe48fff051d17a7bea91 < 07daf4f9750104960a1d60831b2353c0d41f35fb","Linux >= a000c01e60e40e15304ffe48fff051d17a7bea91 < d949992bc3f00027a2c755e860a11950c75f6073","Linux >= a000c01e60e40e15304ffe48fff051d17a7bea91 < 8c283e7b56adce00193837f3311b06662466fb21","Linux 3.0"],"published":"2026-08-22","updated":"2026-10-16","sourceUpdated":"2026-10-16T20:17:41.753","source":"NVD","sourceUrl":"https://nvd.nist.gov/vuln/detail/CVE-2026-74587","references":[{"url":"https://git.kernel.org/stable/c/07daf4f9750104960a1d60831b2353c0d41f35fb","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/10459b03e2d9ee12435e96f587de4d4cacdbf435","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/179676f0166230c80053a392303485b37c93dd33","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/618b5c6d049896fcfabb91afc072954c92cb2693","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/8c283e7b56adce00193837f3311b06662466fb21","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/d949992bc3f00027a2c755e860a11950c75f6073","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/dc67d528c2fa939cec7fe3bf7f3089c8d281ca3d","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/e1bb114e09372fd6e03387ced9ef566da336ed6c","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"}],"tags":["nvd","cve.org"],"epss":0.005,"epssPercentile":0.42613,"ssvc":{"exploitation":"none","automatable":"yes","technicalImpact":"total","timestamp":"2026-10-16T19:01:25.161847Z"},"ingestedAt":"2026-08-23T06:43:33.596Z","slug":"CVE-2026-74587","body":"## Overview\n\nIn 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.\n\n## Remediation\n\nRefer to the linked advisories for vendor-supplied fixes and affected version ranges.","depth":"midnight","depthScore":54,"depthScoreParts":{"impact":53.9,"likelihood":0.1,"exploitation":0,"ransomware":0},"changes":[{"seq":220146,"id":"CVE-2026-74587","ts":1791984787385,"field":"cvss","old":null,"new":"9.8"},{"seq":220145,"id":"CVE-2026-74587","ts":1791984787385,"field":"severity","old":"none","new":"critical"}]}