CVE-2026-89477: Software Security Vulnerability Vulnerability

{
  "schema_version" : "1.4.0",
  "id" : "GHSA-h62f-42cp-xr87",
  "modified" : "2026-09-14T15:32:25Z",
  "published" : "2026-09-11T21:31:28Z",
  "aliases" : [ "CVE-2026-89477" ],
  "details" : "In the Linux kernel, the following vulnerability has been resolved:\n\nsctp: fix NULL deref on untransmitted RECONF completion\n\nsctp_process_strreset_outreq(), sctp_process_strreset_addstrm_out() and\nsctp_process_strreset_resp() complete a pending stream reconfiguration\nrequest by stopping the reconf timer on the transport it was sent on:\n\n\tt = asoc->strreset_chunk->transport;\n\tif (timer_delete(&t->reconf_timer))\n\t\tsctp_transport_put(t);\n\nchunk->transport is assigned by __sctp_packet_append_chunk() when the\nchunk is appended to an outbound packet, and sctp_outq_flush_ctrl() arms\nthe reconf timer at that same point. A request already published in\nasoc->strreset_chunk but not yet transmitted has neither, so completing\nit dereferences NULL.\n\nTwo ways to get there. sctp_send_asconf_del_ip() sets\nasoc->src_out_of_asoc_ok without sending anything when the address being\nremoved is the association's last one, and sctp_outq_flush_ctrl() then\nleaves every non-ASCONF control chunk queued; as only\nsctp_process_asconf_ack() clears that flag, it persists. An unprivileged\nprocess that removes such an address and then asks for a stream reset\npanics the kernel from softirq. A peer needs neither ASCONF nor local\nhelp: sctp_cmd_interpreter() uncorks the outqueue only once the whole\npacket has been processed, so a reply built while walking a RECONF chunk\nstays untransmitted for the rest of that walk, and one RECONF chunk\ncarrying [Incoming SSN Reset Request, Outgoing SSN Reset Request,\nResponse] -- or two RECONF chunks in one packet -- reaches the same\ndereference.\n\n  KASAN: null-ptr-deref in range [0x00000000000001e8-0x00000000000001ef]\n  RIP: 0010:timer_delete+0x67/0x110\n  Call Trace:\n   <IRQ>\n   sctp_process_strreset_addstrm_out (net/sctp/stream.c:832)\n   sctp_sf_do_reconf (net/sctp/sm_statefuns.c:4212)\n   sctp_do_sm (net/sctp/sm_sideeffect.c:1172)\n   sctp_assoc_bh_rcv (net/sctp/associola.c:1044)\n   sctp_rcv (net/sctp/input.c:243)\n   ip_local_deliver (net/ipv4/ip_input.c:262)\n   process_backlog (net/core/dev.c:6680)\n   </IRQ>\n\nA response can only acknowledge a request that was actually sent, so do\nnot match asoc->strreset_chunk while chunk->transport is NULL. Guarding\nthe lookup covers all three completion sites.",
  "severity" : [ {
    "type" : "CVSS_V3",
    "score" : "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H"
  } ],
  "affected" : [ ],
  "references" : [ {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2026-89477"
  }, {
    "type" : "WEB",
    "url" : "https://git.kernel.org/stable/c/0ee697defc0594f1da810ed75d9d643fb46f5318"
  }, {
    "type" : "WEB",
    "url" : "https://git.kernel.org/stable/c/25419f516ea84b1e7d3d55aae5215ac86ece0c66"
  }, {
    "type" : "WEB",
    "url" : "https://git.kernel.org/stable/c/2db9bfa3e27bdea15e05ea70b56bad3d21e570ec"
  }, {
    "type" : "WEB",
    "url" : "https://git.kernel.org/stable/c/53141db979687eae7dc6d29414cefc77034f967e"
  }, {
    "type" : "WEB",
    "url" : "https://git.kernel.org/stable/c/68891125af5a5dfbca728809a16637a869bbe0df"
  }, {
    "type" : "WEB",
    "url" : "https://git.kernel.org/stable/c/77ea60f2d24002c308f224db44a4542c466489af"
  }, {
    "type" : "WEB",
    "url" : "https://git.kernel.org/stable/c/79ff751311e80fa0370007e46a79a6d601685e75"
  }, {
    "type" : "WEB",
    "url" : "https://git.kernel.org/stable/c/b2d6d873b4dfb5b84194061c4b40a1cd85b92ca4"
  } ],
  "database_specific" : {
    "cwe_ids" : [ ],
    "severity" : "HIGH",
    "github_reviewed" : false,
    "github_reviewed_at" : null,
    "nvd_published_at" : "2026-09-11T20:19:29Z"
  }
}