{"cve":"CVE-2026-74586","nvd":{"published":"2026-08-22T16:16:30.687","modified":"2026-10-16T20:17:41.120","status":"Received","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nsctp: clear new_transport when removing a peer\n\nsctp_process_asconf_param() stores a newly added peer transport in\nasoc->new_transport. After all parameters in the ASCONF chunk have been\nprocessed, sctp_sf_do_asconf() uses this pointer to send a HEARTBEAT to the\nnew transport.\n\nAn authenticated ASCONF from a remote SCTP peer can add a transport and\nremove it again with a wildcard DEL-IP parameter in the same chunk. The\nwildcard deletion preserves the transport on which the ASCONF arrived, but\nremoves the newly added transport through\nsctp_assoc_del_nonprimary_peers(). The removal does not clear\nasoc->new_transport, leaving it pointing to the removed transport.\n\nsctp_sf_do_asconf() then creates a HEARTBEAT whose chunk->transport points\nto the removed transport without holding a transport reference. During\nlocal address replacement, src_out_of_asoc_ok keeps this HEARTBEAT on\ncontrol_chunk_list. After the transport is freed by RCU, a successful\nASCONF_ACK for the replacement address releases the queued HEARTBEAT and\nsctp_outq_select_transport() reads the freed transport's state.\n\nThe issue was found during a static audit of SCTP objects. With an\nauthenticated peer, the reproducer triggered the same KASAN report in 2\nof 2 unpatched runs on a KASAN-enabled netdev/main kernel:\n\n  BUG: KASAN: slab-use-after-free in sctp_outq_select_transport\n  Read of size 4 at addr ffff88800b9bd95c by task python3/197\n\n  Call Trace:\n   sctp_outq_select_transport+0x549/0x8b0 [sctp]\n   sctp_outq_flush+0x306/0x2c60 [sctp]\n   sctp_transport_immediate_rtx+0xaf/0x260 [sctp]\n   sctp_process_asconf_ack+0xa48/0xf70 [sctp]\n\n  Allocated by task 197:\n   sctp_transport_new+0x68/0x650 [sctp]\n   sctp_assoc_add_peer+0x258/0x12a0 [sctp]\n   sctp_process_asconf+0x5e9/0x1090 [sctp]\n\n  Last potentially related work creation:\n   __call_rcu_common.constprop.0+0x77/0xb70\n   sctp_assoc_del_nonprimary_peers+0x7c/0xd0 [sctp]\n   sctp_process_asconf+0xd9c/0x1090 [sctp]\n\nThe first invalid access was a four-byte read of transport->state at\nnet/sctp/outqueue.c:833. The same reproducer completed the full\nauthenticated ASCONF and local-address replacement sequence with this\nchange without a KASAN report or oops.\n\nClear new_transport when its peer is removed, before it can be used to\ncreate the HEARTBEAT.","cvss_v4":null,"cvss_v3":{"version":"3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H","score":9.8},"cwes":[],"references":["https://git.kernel.org/stable/c/163847552a571bd55094291f4ffcdc1de0f14a7b","https://git.kernel.org/stable/c/291accf36febce751021888de5f15090f4875b56","https://git.kernel.org/stable/c/31efa656cf6aface26e88f038c14f22ee6ca1500","https://git.kernel.org/stable/c/3b539b317cd052236fed0350364ff1268996ba46","https://git.kernel.org/stable/c/beb33f8ee1ca83acddb2a5ae80f3d22ec550b4c3"],"products":[],"source":"nvd","synced_at":"2026-10-19T22:49:38.260478770+00:00"},"epss":{"cve":"CVE-2026-74586","score":0.005,"percentile":0.42524,"date":"2026-10-25"},"kev":null,"osv":[],"attribution":["This product uses the NVD API but is not endorsed or certified by the NVD.","EPSS scores: FIRST Exploit Prediction Scoring System, https://www.first.org/epss","Known exploited vulnerabilities: CISA Known Exploited Vulnerabilities Catalog, https://www.cisa.gov/known-exploited-vulnerabilities-catalog","Package advisories: OSV (https://osv.dev), from the GitHub Advisory Database, PyPA, Go, RustSec and other ecosystem databases, under CC-BY 4.0 or CC0","CVE records: the CVE Program's CVE List (https://www.cve.org), under its terms of use (https://www.cve.org/Legal/TermsOfUse). CVE is a registered trademark of The MITRE Corporation; this product is not affiliated with the CVE Program."]}