{"cve":"CVE-2026-23125","nvd":{"published":"2026-02-14T15:16:07.740","modified":"2026-10-19T19:17:38.210","status":"Modified","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nsctp: move SCTP_CMD_ASSOC_SHKEY right after SCTP_CMD_PEER_INIT\n\nA null-ptr-deref was reported in the SCTP transmit path when SCTP-AUTH key\ninitialization fails:\n\n  ==================================================================\n  KASAN: null-ptr-deref in range [0x0000000000000018-0x000000000000001f]\n  CPU: 0 PID: 16 Comm: ksoftirqd/0 Tainted: G W 6.6.0 #2\n  RIP: 0010:sctp_packet_bundle_auth net/sctp/output.c:264 [inline]\n  RIP: 0010:sctp_packet_append_chunk+0xb36/0x1260 net/sctp/output.c:401\n  Call Trace:\n\n  sctp_packet_transmit_chunk+0x31/0x250 net/sctp/output.c:189\n  sctp_outq_flush_data+0xa29/0x26d0 net/sctp/outqueue.c:1111\n  sctp_outq_flush+0xc80/0x1240 net/sctp/outqueue.c:1217\n  sctp_cmd_interpreter.isra.0+0x19a5/0x62c0 net/sctp/sm_sideeffect.c:1787\n  sctp_side_effects net/sctp/sm_sideeffect.c:1198 [inline]\n  sctp_do_sm+0x1a3/0x670 net/sctp/sm_sideeffect.c:1169\n  sctp_assoc_bh_rcv+0x33e/0x640 net/sctp/associola.c:1052\n  sctp_inq_push+0x1dd/0x280 net/sctp/inqueue.c:88\n  sctp_rcv+0x11ae/0x3100 net/sctp/input.c:243\n  sctp6_rcv+0x3d/0x60 net/sctp/ipv6.c:1127\n\nThe issue is triggered when sctp_auth_asoc_init_active_key() fails in\nsctp_sf_do_5_1C_ack() while processing an INIT_ACK. In this case, the\ncommand sequence is currently:\n\n- SCTP_CMD_PEER_INIT\n- SCTP_CMD_TIMER_STOP (T1_INIT)\n- SCTP_CMD_TIMER_START (T1_COOKIE)\n- SCTP_CMD_NEW_STATE (COOKIE_ECHOED)\n- SCTP_CMD_ASSOC_SHKEY\n- SCTP_CMD_GEN_COOKIE_ECHO\n\nIf SCTP_CMD_ASSOC_SHKEY fails, asoc->shkey remains NULL, while\nasoc->peer.auth_capable and asoc->peer.peer_chunks have already been set by\nSCTP_CMD_PEER_INIT. This allows a DATA chunk with auth = 1 and shkey = NULL\nto be queued by sctp_datamsg_from_user().\n\nSince command interpretation stops on failure, no COOKIE_ECHO should been\nsent via SCTP_CMD_GEN_COOKIE_ECHO. However, the T1_COOKIE timer has already\nbeen started, and it may enqueue a COOKIE_ECHO into the outqueue later. As\na result, the DATA chunk can be transmitted together with the COOKIE_ECHO\nin sctp_outq_flush_data(), leading to the observed issue.\n\nSimilar to the other places where it calls sctp_auth_asoc_init_active_key()\nright after sctp_process_init(), this patch moves the SCTP_CMD_ASSOC_SHKEY\nimmediately after SCTP_CMD_PEER_INIT, before stopping T1_INIT and starting\nT1_COOKIE. This ensures that if shared key generation fails, authenticated\nDATA cannot be sent. It also allows the T1_INIT timer to retransmit INIT,\ngiving the client another chance to process INIT_ACK and retry key setup.","cvss_v4":null,"cvss_v3":{"version":"3.1","vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H","score":5.5},"cwes":["CWE-476"],"references":["https://git.kernel.org/stable/c/0c4adb1f391a7b92a0405e9d7c05624c0d9f8a65","https://git.kernel.org/stable/c/5a309bedf02ee08b0653215f06c94d61ec7a214a","https://git.kernel.org/stable/c/784428ab1889eb185a1459e9d6bc52df33d572ef","https://git.kernel.org/stable/c/a80c9d945aef55b23b54838334345f20251dad83","https://git.kernel.org/stable/c/bf2b543b3cc4ebb4ab5bca4f8dfa5612035d45b8"],"products":["linux:linux_kernel"],"source":"nvd","synced_at":"2026-10-21T03:43:09.190223697+00:00"},"epss":{"cve":"CVE-2026-23125","score":0.00134,"percentile":0.02891,"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."]}