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CriticalFix available

sctp: don't free the ASCONF's own transport in DEL-IP processing

Type: advisorySources: OSV

In the Linux kernel, the following vulnerability has been resolved: sctp: don't free the ASCONF's own transport in DEL-IP processing sctp_process_asconf() caches the transport the ASCONF chunk is processed against in asconf->transport (== chunk->transport, set once in sctp_rcv()). For an ASCONF located through its Address Parameter by __sctp_rcv_asconf_lookup(), that cached transport corresponds to the Address Parameter, which need not be the packet's source address. sctp_process_asconf_param() rejects a DEL-IP for the packet source address (ADDIP D8, SCTP_ERROR_DEL_SRC_IP), but nothing protects asconf->transport. A single ASCONF can therefore carry, in order: [Address Parameter L] [DEL-IP L] [DEL-IP 0.0.0.0] where L differs from the source. The DEL-IP for L passes the D8 check and calls sctp_assoc_rm_peer() on the transport that asconf->transport still points at, freeing it (RCU-deferred). The following wildcard DEL-IP then reuses the now-dangling asconf->transport in sctp_assoc_set_primary() and sctp_assoc_del_nonprimary_peers(): set_primary() dereferences the freed transport (->ipaddr, ->state) and plants the dangling pointer into asoc->peer.primary_path / active_path, and del_nonprimary_peers(), keeping only the pointer that is no longer on the list, removes every real transport, leaving the association with a transport_count of 0 and primary_path/active_path pointing at freed memory. Reject a DEL-IP that targets the transport the ASCONF is being processed against, mirror

Products
Kernel
Affected versions
Not specified
Fixed versions
5.10.265, 5.15.216, 6.1.183, 6.12.101, 6.18.42, 6.6.148, 7.1.6
CVEs
CVE-2026-64564
Confirmed fixed CVEs
Not specified
Updated in this feed
6 Nov 2026, 02:37 UTC · Revision 1

Source evidence

sctp: don't free the ASCONF's own transport in DEL-IP processing

core-osv · Original source

Published 4 Aug 2026, 06:23 UTC

In the Linux kernel, the following vulnerability has been resolved: sctp: don't free the ASCONF's own transport in DEL-IP processing sctp_process_asconf() caches the transport the ASCONF chunk is processed against in asconf->transport (== chunk->transport, set once in sctp_rcv()). For an ASCONF located through its Address Parameter by __sctp_rcv_asconf_lookup(), that cached transport corresponds to the Address Parameter, which need not be the packet's source address. sctp_process_asconf_param() rejects a DEL-IP for the packet source address (ADDIP D8, SCTP_ERROR_DEL_SRC_IP), but nothing protects asconf->transport. A single ASCONF can therefore carry, in order: [Address Parameter L] [DEL-IP L] [DEL-IP 0.0.0.0] where L differs from the source. The DEL-IP for L passes the D8 check and calls sctp_assoc_rm_peer() on the transport that asconf->transport still points at, freeing it (RCU-deferred). The following wildcard DEL-IP then reuses the now-dangling asconf->transport in sctp_assoc_set_primary() and sctp_assoc_del_nonprimary_peers(): set_primary() dereferences the freed transport (->ipaddr, ->state) and plants the dangling pointer into asoc->peer.primary_path / active_path, and del_nonprimary_peers(), keeping only the pointer that is no longer on the list, removes every real transport, leaving the association with a transport_count of 0 and primary_path/active_path pointing at freed memory. Reject a DEL-IP that targets the transport the ASCONF is being processed against, mirror

osv:CVE-2026-64564

Kernel

Fixed versions: 5.10.265, 5.15.216, 6.1.183, 6.6.148, 6.12.101, 6.18.42, 7.1.6

Complete source record
{
  "id": "46c8f0d7fc6464dbab94698dd4d3f3e7b7b9138748f66c1b330646d96f4d3867",
  "url": "https://osv.dev/vulnerability/CVE-2026-64564",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "sctp: don't free the ASCONF's own transport in DEL-IP processing",
    "summary": "In the Linux kernel, the following vulnerability has been resolved: sctp: don't free the ASCONF's own transport in DEL-IP processing sctp_process_asconf() caches the transport the ASCONF chunk is processed against in asconf->transport (== chunk->transport, set once in sctp_rcv()). For an ASCONF located through its Address Parameter by __sctp_rcv_asconf_lookup(), that cached transport corresponds to the Address Parameter, which need not be the packet's source address. sctp_process_asconf_param() rejects a DEL-IP for the packet source address (ADDIP D8, SCTP_ERROR_DEL_SRC_IP), but nothing protects asconf->transport. A single ASCONF can therefore carry, in order: [Address Parameter L] [DEL-IP L] [DEL-IP 0.0.0.0] where L differs from the source. The DEL-IP for L passes the D8 check and calls sctp_assoc_rm_peer() on the transport that asconf->transport still points at, freeing it (RCU-deferred). The following wildcard DEL-IP then reuses the now-dangling asconf->transport in sctp_assoc_set_primary() and sctp_assoc_del_nonprimary_peers(): set_primary() dereferences the freed transport (->ipaddr, ->state) and plants the dangling pointer into asoc->peer.primary_path / active_path, and del_nonprimary_peers(), keeping only the pointer that is no longer on the list, removes every real transport, leaving the association with a transport_count of 0 and primary_path/active_path pointing at freed memory. Reject a DEL-IP that targets the transport the ASCONF is being processed against, mirror",
    "evidence": "osv:CVE-2026-64564",
    "products": [
      {
        "name": {
          "value": "Kernel",
          "evidence": "/affected/1/package/name"
        },
        "prerequisites": [],
        "fixed_versions": [
          {
            "value": "5.10.265",
            "evidence": "/affected/1/ranges"
          },
          {
            "value": "5.15.216",
            "evidence": "/affected/1/ranges"
          },
          {
            "value": "6.1.183",
            "evidence": "/affected/1/ranges"
          },
          {
            "value": "6.6.148",
            "evidence": "/affected/1/ranges"
          },
          {
            "value": "6.12.101",
            "evidence": "/affected/1/ranges"
          },
          {
            "value": "6.18.42",
            "evidence": "/affected/1/ranges"
          },
          {
            "value": "7.1.6",
            "evidence": "/affected/1/ranges"
          }
        ],
        "affected_versions": []
      }
    ],
    "severity": "critical",
    "structured": {
      "id": "CVE-2026-64564",
      "aliases": [
        "CVE-2026-64564"
      ],
      "metrics": [
        {
          "type": "CVSS_V3",
          "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H"
        }
      ],
      "affected": [
        {
          "ranges": [
            {
              "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
              "type": "GIT",
              "events": [
                {
                  "introduced": "42e30bf3463cd37d73839376662cb79b4d5c416c"
                },
                {
                  "fixed": "a9ce31be4cb1a5dd82b3e0a1d0c3e7cbdcd31293"
                },
                {
                  "fixed": "a63afa1f9b12d5293cbe0b77fd45dc0632533a13"
                },
                {
                  "fixed": "2b324ba3494ae958cba16a453e3e71489b4de7fc"
                },
                {
                  "fixed": "fedeb4468987bcaff85fe3061de5ae052d414740"
                },
                {
                  "fixed": "74e8f3e7114f0e26d1b2c4c048044db9fcc27603"
                },
                {
                  "fixed": "85aca407c560aba81b5ce9d3d6cf94c74077d19b"
                },
                {
                  "fixed": "d136b29bf91dd8e3161281b87de597b7311d9462"
                },
                {
                  "fixed": "9b2854f86f0b56e9027d68e7a3fc909d1a9b566f"
                }
              ]
            }
          ],
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-64564.json"
          }
        },
        {
          "ranges": [
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "2.6.25"
                },
                {
                  "fixed": "5.10.265"
                }
              ]
            },
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "5.11.0"
                },
                {
                  "fixed": "5.15.216"
                }
              ]
            },
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "5.16.0"
                },
                {
                  "fixed": "6.1.183"
                }
              ]
            },
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "6.2.0"
                },
                {
                  "fixed": "6.6.148"
                }
              ]
            },
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "6.7.0"
                },
                {
                  "fixed": "6.12.101"
                }
              ]
            },
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "6.13.0"
                },
                {
                  "fixed": "6.18.42"
                }
              ]
            },
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "6.19.0"
                },
                {
                  "fixed": "7.1.6"
                }
              ]
            }
          ],
          "package": {
            "name": "Kernel",
            "ecosystem": "Linux"
          },
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-64564.json"
          }
        }
      ],
      "modified": "2026-10-28T02:30:46.149058521Z",
      "provider": "osv",
      "references": [
        "https://git.kernel.org/stable/c/2b324ba3494ae958cba16a453e3e71489b4de7fc",
        "https://git.kernel.org/stable/c/74e8f3e7114f0e26d1b2c4c048044db9fcc27603",
        "https://git.kernel.org/stable/c/85aca407c560aba81b5ce9d3d6cf94c74077d19b",
        "https://git.kernel.org/stable/c/9b2854f86f0b56e9027d68e7a3fc909d1a9b566f",
        "https://git.kernel.org/stable/c/a63afa1f9b12d5293cbe0b77fd45dc0632533a13",
        "https://git.kernel.org/stable/c/a9ce31be4cb1a5dd82b3e0a1d0c3e7cbdcd31293",
        "https://git.kernel.org/stable/c/d136b29bf91dd8e3161281b87de597b7311d9462",
        "https://git.kernel.org/stable/c/fedeb4468987bcaff85fe3061de5ae052d414740",
        "https://matrix.tencent.com/en/2026/08/06/sctphantom-CVE-2026-64564",
        "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/64xxx/CVE-2026-64564.json",
        "https://nvd.nist.gov/vuln/detail/CVE-2026-64564",
        "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git"
      ],
      "provider_metadata": {
        "cna_assigner": "Linux",
        "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/64xxx/CVE-2026-64564.json"
      }
    },
    "related_cves": [
      {
        "value": "CVE-2026-64564",
        "evidence": "/id"
      }
    ],
    "security_relevant": true,
    "severity_evidence": "/severity/0/score"
  },
  "source_id": "core-osv",
  "document_id": 514338,
  "published_at": "2026-08-04T06:23:23.339+00:00"
}