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GHSA-47R2-M88P-RGJM

Vulnerability from github – Published: 2026-09-11 21:31 – Updated: 2026-09-14 15:32
VLAI
Details

In the Linux kernel, the following vulnerability has been resolved:

sctp: drop a chunk if its transport was removed

sctp_rcv() resolves the transport once per packet and leaves it in chunk->transport. The lookup reference, or the one sctp_add_backlog() takes if the socket is owned by userspace, keeps it around until the chunk has been processed.

An authenticated ASCONF DEL-IP can remove it in the meantime. sctp_assoc_rm_peer() takes the transport out of the association and calls sctp_transport_free(), which tags it dead and drops the reference the association held. There is a window on both paths: the packet can sit on the socket backlog, and on the direct path the lookup completes before bh_lock_sock().

The DATA chunk in that packet puts the removed transport back into asoc->peer.last_data_from. Once the packet is done that reference goes away and the transport is freed by RCU, so the next delayed SACK carries the pointer into the SACK chunk and sctp_outq_select_transport() reads the freed transport's state.

Drop the chunk in sctp_inq_push(), next to the existing rcvr->dead check. Both paths reach it with the association's socket lock held. The peer retransmits it.

Severity
9.8 (Critical)
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
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{
  "affected": [],
  "aliases": [
    "CVE-2026-89478"
  ],
  "database_specific": {
    "cwe_ids": [],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-09-11T20:19:29Z",
    "severity": "CRITICAL"
  },
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nsctp: drop a chunk if its transport was removed\n\nsctp_rcv() resolves the transport once per packet and leaves it in\nchunk-\u003etransport. The lookup reference, or the one sctp_add_backlog() takes\nif the socket is owned by userspace, keeps it around until the chunk has\nbeen processed.\n\nAn authenticated ASCONF DEL-IP can remove it in the meantime.\nsctp_assoc_rm_peer() takes the transport out of the association and calls\nsctp_transport_free(), which tags it dead and drops the reference the\nassociation held. There is a window on both paths: the packet can sit on\nthe socket backlog, and on the direct path the lookup completes before\nbh_lock_sock().\n\nThe DATA chunk in that packet puts the removed transport back into\nasoc-\u003epeer.last_data_from. Once the packet is done that reference goes\naway and the transport is freed by RCU, so the next delayed SACK carries\nthe pointer into the SACK chunk and sctp_outq_select_transport() reads the\nfreed transport\u0027s state.\n\nDrop the chunk in sctp_inq_push(), next to the existing rcvr-\u003edead check.\nBoth paths reach it with the association\u0027s socket lock held. The peer\nretransmits it.",
  "id": "GHSA-47r2-m88p-rgjm",
  "modified": "2026-09-14T15:32:26Z",
  "published": "2026-09-11T21:31:28Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-89478"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/03a9d10ecf71f54b2af8020935f2033d4a132be5"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/0422b092a3d43ca462932ff9f747731ca078d1d4"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/1035bdef1efb9b1076d1a57b81e08c637ff08ecc"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/3537961df2163258bddc230db0e18dc14e925ea6"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/3fc072e7cb4a0ff251d13cfc2d24f62489cd9386"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/928fd7920ba37cc5637a211b9be979083413a2fa"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/c6c86a5e62a4fec36692ddd64b9144b660f71f96"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/d7cb5ad832095dc4becfdb2a36007ffd50e49fb0"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H",
      "type": "CVSS_V3"
    }
  ]
}



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