{"id":"AZL-77751","summary":"CVE-2026-23125 affecting package kernel for versions less than 6.6.126.1-1","details":"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-\u003eshkey remains NULL, while\nasoc-\u003epeer.auth_capable and asoc-\u003epeer.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.","modified":"2026-08-28T17:47:33.454214336Z","published":"2026-02-14T15:16:07Z","upstream":["CVE-2026-23125"],"references":[{"type":"WEB","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-23125"}],"affected":[{"package":{"name":"kernel","ecosystem":"Azure Linux:3","purl":"pkg:rpm/azure-linux/kernel"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"6.6.126.1-1"}]}],"database_specific":{"source":"https://github.com/microsoft/AzureLinuxVulnerabilityData/blob/main/osv/AZL-77751.json"}}],"schema_version":"1.9.0"}