CVE-2026-64564 (GCVE-0-2026-64564)

Vulnerability from cvelistv5 – Published: 2026-08-04 06:23 – Updated: 2026-08-09 03:38
VLAI
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, mirroring the existing source-address guard, so the wildcard branch can never reuse a freed transport.
Severity
9.8 (Critical)
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Assigner
References
Impacted products
Vendor Product Version
Linux Linux Affected: 42e30bf3463cd37d73839376662cb79b4d5c416c , < fedeb4468987bcaff85fe3061de5ae052d414740 (git)
Affected: 42e30bf3463cd37d73839376662cb79b4d5c416c , < 74e8f3e7114f0e26d1b2c4c048044db9fcc27603 (git)
Affected: 42e30bf3463cd37d73839376662cb79b4d5c416c , < 85aca407c560aba81b5ce9d3d6cf94c74077d19b (git)
Affected: 42e30bf3463cd37d73839376662cb79b4d5c416c , < d136b29bf91dd8e3161281b87de597b7311d9462 (git)
Affected: 42e30bf3463cd37d73839376662cb79b4d5c416c , < 9b2854f86f0b56e9027d68e7a3fc909d1a9b566f (git)
Create a notification for this product.
Linux Linux Affected: 2.6.25
Unaffected: 0 , < 2.6.25 (semver)
Unaffected: 6.6.148 , ≤ 6.6.* (semver)
Unaffected: 6.12.101 , ≤ 6.12.* (semver)
Unaffected: 6.18.42 , ≤ 6.18.* (semver)
Unaffected: 7.1.6 , ≤ 7.1.* (semver)
Unaffected: 7.2-rc5 , ≤ * (original_commit_for_fix)
Create a notification for this product.
Show details on NVD website
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          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nsctp: don\u0027t free the ASCONF\u0027s own transport in DEL-IP processing\n\nsctp_process_asconf() caches the transport the ASCONF chunk is processed\nagainst in asconf-\u003etransport (== chunk-\u003etransport, set once in sctp_rcv()).\nFor an ASCONF located through its Address Parameter by\n__sctp_rcv_asconf_lookup(), that cached transport corresponds to the\nAddress Parameter, which need not be the packet\u0027s source address.\n\nsctp_process_asconf_param() rejects a DEL-IP for the packet source address\n(ADDIP D8, SCTP_ERROR_DEL_SRC_IP), but nothing protects asconf-\u003etransport.\nA single ASCONF can therefore carry, in order:\n\n    [Address Parameter L] [DEL-IP L] [DEL-IP 0.0.0.0]\n\nwhere L differs from the source. The DEL-IP for L passes the D8 check and\ncalls sctp_assoc_rm_peer() on the transport that asconf-\u003etransport still\npoints at, freeing it (RCU-deferred). The following wildcard DEL-IP then\nreuses the now-dangling asconf-\u003etransport in sctp_assoc_set_primary() and\nsctp_assoc_del_nonprimary_peers(): set_primary() dereferences the freed\ntransport (-\u003eipaddr, -\u003estate) and plants the dangling pointer into\nasoc-\u003epeer.primary_path / active_path, and del_nonprimary_peers(), keeping\nonly the pointer that is no longer on the list, removes every real\ntransport, leaving the association with a transport_count of 0 and\nprimary_path/active_path pointing at freed memory.\n\nReject a DEL-IP that targets the transport the ASCONF is being processed\nagainst, mirroring the existing source-address guard, so the wildcard\nbranch can never reuse a freed transport."
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              "value": "AV:N - The bug is in SCTP ASCONF receive processing (sctp_rcv \u2192 sctp_sf_do_asconf \u2192 sctp_process_asconf \u2192 sctp_process_asconf_param); a remote peer triggers it by sending a crafted ASCONF over IP/IPv6 on an established association, matching kernel guidance that net/ stack bugs reachable via received packets are Network.\nAC:L - A single attacker-controlled ASCONF with [Address Parameter L][DEL-IP L][DEL-IP 0.0.0.0] reliably frees asconf-\u003etransport then reuses it in the same softirq; the peer fully controls multi-homing, serial, and parameter order, with no race or other condition outside attacker influence.\nPR:N - Any remote SCTP peer that completes a normal association with ADD-IP negotiated can send the ASCONF; SCTP-AUTH keys come from the handshake the peer itself performs (or addip_noauth), and no local credentials or capabilities on the target are required.\nUI:N - Exploitation requires only attacker-sent SCTP packets processed automatically in the receive/state-machine path; no victim user action such as opening a file or mounting a device is needed.\nS:U - Impact is confined to the vulnerable host kernel (sctp_transport UAF / crash or privilege escalation) and does not cross a VM, IOMMU, or other security-authority boundary.\nC:H - This is a heap use-after-free of an sctp_transport planted into primary_path/active_path after RCU-deferred free; freed-object reuse yields arbitrary kernel read primitives, scored High per UAF guidance.\nI:H - The same transport UAF enables heap spraying and write/control-flow hijacking via later dereferences of the dangling primary_path/active_path, so integrity impact is High.\nA:H - set_primary() immediately dereferences the freed transport and leaves the association with transport_count 0 and dangling path pointers, causing a reproducible kernel oops/panic on subsequent use, which is High availability impact."
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The DEL-IP for L passes the D8 check and\\ncalls sctp_assoc_rm_peer() on the transport that asconf-\u003etransport still\\npoints at, freeing it (RCU-deferred). The following wildcard DEL-IP then\\nreuses the now-dangling asconf-\u003etransport in sctp_assoc_set_primary() and\\nsctp_assoc_del_nonprimary_peers(): set_primary() dereferences the freed\\ntransport (-\u003eipaddr, -\u003estate) and plants the dangling pointer into\\nasoc-\u003epeer.primary_path / active_path, and del_nonprimary_peers(), keeping\\nonly the pointer that is no longer on the list, removes every real\\ntransport, leaving the association with a transport_count of 0 and\\nprimary_path/active_path pointing at freed memory.\\n\\nReject a DEL-IP that targets the transport the ASCONF is being processed\\nagainst, mirroring the existing source-address guard, so the wildcard\\nbranch can never reuse a freed transport.\"}],\"affected\":[{\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\",\"affectedData\":[{\"vendor\":\"Linux\",\"product\":\"Linux\",\"defaultStatus\":\"unaffected\",\"programFiles\":[\"net/sctp/sm_make_chunk.c\"],\"repo\":\"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git\",\"versions\":[{\"version\":\"42e30bf3463cd37d73839376662cb79b4d5c416c\",\"lessThan\":\"fedeb4468987bcaff85fe3061de5ae052d414740\",\"versionType\":\"git\",\"status\":\"affected\"},{\"version\":\"42e30bf3463cd37d73839376662cb79b4d5c416c\",\"lessThan\":\"74e8f3e7114f0e26d1b2c4c048044db9fcc27603\",\"versionType\":\"git\",\"status\":\"affected\"},{\"version\":\"42e30bf3463cd37d73839376662cb79b4d5c416c\",\"lessThan\":\"85aca407c560aba81b5ce9d3d6cf94c74077d19b\",\"versionType\":\"git\",\"status\":\"affected\"},{\"version\":\"42e30bf3463cd37d73839376662cb79b4d5c416c\",\"lessThan\":\"d136b29bf91dd8e3161281b87de597b7311d9462\",\"versionType\":\"git\",\"status\":\"affected\"},{\"version\":\"42e30bf3463cd37d73839376662cb79b4d5c416c\",\"lessThan\":\"9b2854f86f0b56e9027d68e7a3fc909d1a9b566f\",\"versionType\":\"git\",\"status\":\"affected\"}]},{\"vendor\":\"Linux\",\"product\":\"Linux\",\"defaultStatus\":\"affected\",\"programFiles\":[\"net/sctp/sm_make_chunk.c\"],\"repo\":\"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git\",\"versions\":[{\"version\":\"2.6.25\",\"status\":\"affected\"},{\"version\":\"0\",\"lessThan\":\"2.6.25\",\"versionType\":\"semver\",\"status\":\"unaffected\"},{\"version\":\"6.6.148\",\"lessThanOrEqual\":\"6.6.*\",\"versionType\":\"semver\",\"status\":\"unaffected\"},{\"version\":\"6.12.101\",\"lessThanOrEqual\":\"6.12.*\",\"versionType\":\"semver\",\"status\":\"unaffected\"},{\"version\":\"6.18.42\",\"lessThanOrEqual\":\"6.18.*\",\"versionType\":\"semver\",\"status\":\"unaffected\"},{\"version\":\"7.1.6\",\"lessThanOrEqual\":\"7.1.*\",\"versionType\":\"semver\",\"status\":\"unaffected\"},{\"version\":\"7.2-rc5\",\"lessThanOrEqual\":\"*\",\"versionType\":\"original_commit_for_fix\",\"status\":\"unaffected\"}]}]}],\"metrics\":{\"cvssMetricV31\":[{\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\",\"type\":\"Secondary\",\"cvssData\":{\"version\":\"3.1\",\"vectorString\":\"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H\",\"baseScore\":9.8,\"baseSeverity\":\"CRITICAL\",\"attackVector\":\"NETWORK\",\"attackComplexity\":\"LOW\",\"privilegesRequired\":\"NONE\",\"userInteraction\":\"NONE\",\"scope\":\"UNCHANGED\",\"confidentialityImpact\":\"HIGH\",\"integrityImpact\":\"HIGH\",\"availabilityImpact\":\"HIGH\"},\"exploitabilityScore\":3.9,\"impactScore\":5.9}]},\"references\":[{\"url\":\"https://git.kernel.org/stable/c/74e8f3e7114f0e26d1b2c4c048044db9fcc27603\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/85aca407c560aba81b5ce9d3d6cf94c74077d19b\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/9b2854f86f0b56e9027d68e7a3fc909d1a9b566f\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/d136b29bf91dd8e3161281b87de597b7311d9462\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/fedeb4468987bcaff85fe3061de5ae052d414740\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://matrix.tencent.com/en/2026/08/06/sctphantom-CVE-2026-64564\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"http://www.openwall.com/lists/oss-security/2026/08/06/13\",\"source\":\"af854a3a-2127-422b-91ae-364da2661108\"},{\"url\":\"http://www.openwall.com/lists/oss-security/2026/08/06/3\",\"source\":\"af854a3a-2127-422b-91ae-364da2661108\"},{\"url\":\"http://www.openwall.com/lists/oss-security/2026/08/06/4\",\"source\":\"af854a3a-2127-422b-91ae-364da2661108\"},{\"url\":\"http://www.openwall.com/lists/oss-security/2026/08/07/1\",\"source\":\"af854a3a-2127-422b-91ae-364da2661108\"},{\"url\":\"http://www.openwall.com/lists/oss-security/2026/08/07/2\",\"source\":\"af854a3a-2127-422b-91ae-364da2661108\"},{\"url\":\"http://www.openwall.com/lists/oss-security/2026/08/07/8\",\"source\":\"af854a3a-2127-422b-91ae-364da2661108\"}]}}",
    "suse_vex": {
      "aggregate_severity": "important",
      "current_release_date": "2026-08-07T23:44:04Z",
      "cve": "CVE-2026-64564",
      "id": "CVE-2026-64564",
      "initial_release_date": "2026-08-06T23:56:41Z",
      "product_status:first_fixed": "143",
      "product_status:known_affected": "296",
      "source": "SUSE CSAF VEX",
      "status": "interim",
      "title": "SUSE CVE CVE-2026-64564",
      "url": "https://ftp.suse.com/pub/projects/security/csaf-vex/cve-2026-64564.json",
      "version": "4"
    }
  }
}



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