{
  "affected": [
    {
      "ranges": [
        {
          "events": [
            {
              "introduced": "81054476453640159149cb6704e834893e16736b"
            },
            {
              "fixed": "77ea60f2d24002c308f224db44a4542c466489af"
            },
            {
              "fixed": "25419f516ea84b1e7d3d55aae5215ac86ece0c66"
            },
            {
              "fixed": "0ee697defc0594f1da810ed75d9d643fb46f5318"
            },
            {
              "fixed": "2db9bfa3e27bdea15e05ea70b56bad3d21e570ec"
            }
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "type": "GIT"
        }
      ]
    },
    {
      "package": {
        "ecosystem": "Linux",
        "name": "Kernel"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "4.11.0"
            },
            {
              "fixed": "6.12.109"
            }
          ],
          "type": "ECOSYSTEM"
        },
        {
          "events": [
            {
              "introduced": "6.13.0"
            },
            {
              "fixed": "6.18.50"
            }
          ],
          "type": "ECOSYSTEM"
        },
        {
          "events": [
            {
              "introduced": "6.19.0"
            },
            {
              "fixed": "7.2.4"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "database_specific": {
    "cna_assigner": "Linux",
    "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/89xxx/CVE-2026-89477.json"
  },
  "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-\u003estrreset_chunk-\u003etransport;\n\tif (timer_delete(\u0026t-\u003ereconf_timer))\n\t\tsctp_transport_put(t);\n\nchunk-\u003etransport 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-\u003estrreset_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-\u003esrc_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   \u003cIRQ\u003e\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   \u003c/IRQ\u003e\n\nA response can only acknowledge a request that was actually sent, so do\nnot match asoc-\u003estrreset_chunk while chunk-\u003etransport is NULL. Guarding\nthe lookup covers all three completion sites.",
  "id": "CVE-2026-89477",
  "modified": "2026-09-13T03:30:20.260794118Z",
  "published": "2026-09-11T19:43:33.851Z",
  "references": [
    {
      "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/77ea60f2d24002c308f224db44a4542c466489af"
    },
    {
      "type": "ADVISORY",
      "url": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/89xxx/CVE-2026-89477.json"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-89477"
    },
    {
      "type": "PACKAGE",
      "url": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git"
    }
  ],
  "schema_version": "1.9.0",
  "summary": "sctp: fix NULL deref on untransmitted RECONF completion"
}