CriticalCVE-2026-64564

    Linux Kernel: security vulnerability (CVE-2026-64564)

    Published Last modified Sources: SUSE, SingCERT, Red Hat, Ubuntu, Debian, Debian LTS, CVE.org, Msrc Update Guide, BSI

    What is affected, what to do

    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.

    An exploit is publicly available. Update Linux Kernel to version 5.10.265, Linux Kernel to version 5.15.216, Linux Kernel to version 6.1.183.

    Affected
    • Linux Kernel lt 2.6.25..5.10.265
    • Linux Kernel lt 5.11..5.15.216
    • Linux Kernel lt 5.16..6.1.183
    • Linux Kernel lt 6.2..6.6.148
    • Linux Kernel lt 6.7..6.12.101
    • Linux Kernel lt 6.13..6.18.42
    • Linux Kernel lt 6.19..7.1.6
    Fixed in
    • Linux Kernel 5.10.265
    • Linux Kernel 5.15.216
    • Linux Kernel 6.1.183
    • Linux Kernel 6.6.148
    • Linux Kernel 6.12.101
    • Linux Kernel 6.18.42
    • Linux Kernel 7.1.6
    • Linux Kernel 7.2

    Not sure whether and how you are affected? Ask a question about this vulnerability

    Metrics

    9.8

    Priority

    XIEM Effective CVSS: highest available CVSS rating from NVD and vendor data.

    Source: Vendor (CNA), CVSS v3

    9.8

    CVSS v3

    Severity Critical on the scale from 0 to 10.

    Source: SUSE, SingCERT, Red Hat, Ubuntu, Debian, Debian LTS, CVE.org, Msrc Update Guide, BSI

    1.4 %

    EPSS score

    Moderate — model estimates 1-10% exploitation likelihood.

    Source: FIRST EPSS, percentile 72.9

    Show all metrics
    Severity
    Critical
    Priority (0–325)

    The priority score is a consolidated metric that condenses several individual signals into a single, action-guiding ranking: technical severity (CVSS), exploitation likelihood (EPSS), known-exploited status (KEV) and the context of the affected asset. The aim is to answer the only truly important question in vulnerability management: what first?

    Read in glossary
    113.92 Methodology
    Exploit maturity

    An exploit is code or a technique that specifically uses a concrete vulnerability to force unintended behaviour — such as executing code or escalating privileges. It is the tool that turns a theoretical flaw into a practical attack.

    Read in glossary
    PoC (publicly reported)
    XIEM Effective CVSS

    XIEM® is the tiered managed-security operating model from NEOSEC and a registered trademark of NEOSEC GmbH. It extends classic SIEM — the central collection, normalisation and correlation of security-relevant events — with endpoint forensics, network visibility and deception technology, and consolidates them into three building tiers: Sentry, Orchestrate and Command.

    Read in glossary
    9.8 Methodology
    CVSS v3

    CVSS is the globally established, open standard for assessing the technical severity of a vulnerability on a scale from 0 to 10. It describes how easily a flaw can be exploited and what damage it can cause — but not how likely its actual exploitation is. CVSS and the complementary EPSS deliberately answer different questions.

    Read in glossary
    9.8
    EPSS score

    The EPSS score is the absolute model output for an individual vulnerability: the estimated probability of real-world exploitation within the next 30 days, expressed as a value between 0 and 1 (i.e. 0 % to 100 %). A score of 0.42 means „the model estimates a 42 % chance of real-world exploitation within 30 days“.

    Read in glossary
    1.4 %
    Moderate — model estimates 1-10% exploitation likelihood.
    EPSS percentile

    The EPSS percentile is the relative position of a vulnerability within all EPSS-scored CVEs, expressed as a value between 0 and 1. A percentile of 0.90 means „this CVE has a higher EPSS score than 90 % of all other scored CVEs“. Unlike the EPSS score, it is not a probability — but a positioning within a ranking.

    Read in glossary
    72.9
    High — this CVE ranks above the median of all CVEs scored today (rank ≥ 36%).
    KEV status

    The KEV catalogue is a list maintained by the US authority CISA of vulnerabilities for which active exploitation in the wild has been confirmed. It answers not the question „how severe?“ but „is it already being attacked?“ — thereby sharply prioritising patching.

    Read in glossary
    —
    Published

    Detection rules

    No NEOSEC detection rule is available for this vulnerability yet.

    Classification under NIS2 and CRA

    Rule-based classification from exploitation status and severity. It does not replace a case-by-case assessment.

    NIS2

    NIS2 is EU Directive (EU) 2022/2555 to raise the level of cybersecurity across the Union. It substantially broadens obligations compared with the first NIS directive: more sectors, mandatory risk management, staged reporting duties and personal accountability of senior management.

    Read in glossary
    High technical severity: assess and remediate the vulnerability in vulnerability handling under Art. 21(2)(e) NIS2 and document the decision.
    CRA

    The CRA is EU Regulation (EU) 2024/2847 setting horizontal cybersecurity requirements for „products with digital elements“ — from industrial controllers and software to connected consumer devices. For the first time manufacturers must ensure security across the entire product lifecycle, handle vulnerabilities and provide security updates.

    Read in glossary
    From 11.12.2027, Annex I Part II CRA requires manufacturers of affected products with digital elements to handle vulnerabilities without delay and provide security updates.
    ISO/IEC 27001

    ISO/IEC 27001 is the internationally leading standard for an information security management system (ISMS). It describes a risk-based, process-oriented framework to systematically plan, implement, review and improve information security.

    Read in glossary
    Control A.8.8, management of technical vulnerabilities: assess relevance to your systems, plan remediation and keep evidence.

    Description

    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.

    Source: suse_csaf, CSA/SingCERT, redhat_csaf, Ubuntu Security Notices, Debian Security Advisories, Debian LTS Advisories, cvelistv5, NVD (NIST), CVE.org (MITRE), Microsoft Security Update Guide, BSI WID Portal, BSI CSAF

    Affected products

    The following versions are affected. Older releases of the same product line are also vulnerable unless stated otherwise.

    Affected products
    Affected versionsFixed in
    LinuxLinux
    • 6.7 – < 6.12.101
    • 6.2 – < 6.6.148
    • 5.11 – < 5.15.216
    • 5.16 – < 6.1.183
    • 6.13 – < 6.18.42
    • —
    • 2.6.25 – < 5.10.265
    • 6.19 – < 7.1.6
    • 6.12.101
    • 6.6.148
    • 5.15.216
    • 6.1.183
    • 6.18.42
    • 7.2
    • 5.10.265
    • 7.1.6

    Vendors and products

    Affected operating systems

    Affected operating systems
    Linuxdebianlinuxbookworm
    Linuxdebianlinuxtrixie
    Linuxdebianlinux-6.12bookworm
    Linuxubuntulinux-gcp-5.15focal

    Public exploit references

    Publicly reported proof-of-concepts, exploit modules and detection templates for this vulnerability. NEOSEC links to the original sources only and does not provide any exploit code.

    Public exploit references
    PoC-in-GitHub (nomi-sec)yc-mk8s-sctphantom-mitigation (opens in a new tab)github.comPoC (publicly reported)reported, not verified
    PoC-in-GitHub (nomi-sec)sctphantom (opens in a new tab)github.comPoC (publicly reported)reported, not verified
    PoC-in-GitHub (nomi-sec)CVE-2026-64564 (opens in a new tab)github.comPoC (publicly reported)reported, not verified
    PoC-in-GitHub (nomi-sec)CVE-2026-64564 (opens in a new tab)github.comPoC (publicly reported)reported, not verified

    References & sources

    Changes to this CVE

    Who changed this CVE and when: NVD (analysis, affected products, CVSS), the CVE publisher (CNA) and additional providers such as CISA (ADP).

    1. Record modifiedCISA ADP

      Weakness type: CWE-416

      Show the original change
      Individual changes of this event as published by NVD
      TypeActionBeforeAfter
      Weakness type (CWE)added
      —
      CWE-416

      Source identifier: 134c704f-9b21-4f2e-91b3-4a467353bcc0

    2. Record modifiedLinux

      Show 18 original changes
      Individual changes of this event as published by NVD
      TypeActionBeforeAfter
      Referenceadded
      —
      https://git.kernel.org/stable/c/2b324ba3494ae958cba16a453e3e71489b4de7fc
      Referenceadded
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      https://git.kernel.org/stable/c/74e8f3e7114f0e26d1b2c4c048044db9fcc27603
      Referenceadded
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      https://git.kernel.org/stable/c/85aca407c560aba81b5ce9d3d6cf94c74077d19b
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      https://git.kernel.org/stable/c/9b2854f86f0b56e9027d68e7a3fc909d1a9b566f
      Referenceadded
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      https://git.kernel.org/stable/c/a63afa1f9b12d5293cbe0b77fd45dc0632533a13
      Referenceadded
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      https://git.kernel.org/stable/c/a9ce31be4cb1a5dd82b3e0a1d0c3e7cbdcd31293
      Referenceadded
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      https://git.kernel.org/stable/c/d136b29bf91dd8e3161281b87de597b7311d9462
      Referenceadded
      —
      https://git.kernel.org/stable/c/fedeb4468987bcaff85fe3061de5ae052d414740
      Referenceadded
      —
      https://matrix.tencent.com/en/2026/08/06/sctphantom-CVE-2026-64564
      Referenceremoved
      https://git.kernel.org/stable/c/2b324ba3494ae958cba16a453e3e71489b4de7fc
      —
      Referenceremoved
      https://git.kernel.org/stable/c/74e8f3e7114f0e26d1b2c4c048044db9fcc27603
      —
      Referenceremoved
      https://git.kernel.org/stable/c/85aca407c560aba81b5ce9d3d6cf94c74077d19b
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      Referenceremoved
      https://git.kernel.org/stable/c/9b2854f86f0b56e9027d68e7a3fc909d1a9b566f
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      Referenceremoved
      https://git.kernel.org/stable/c/a63afa1f9b12d5293cbe0b77fd45dc0632533a13
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      Referenceremoved
      https://git.kernel.org/stable/c/a9ce31be4cb1a5dd82b3e0a1d0c3e7cbdcd31293
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      Referenceremoved
      https://git.kernel.org/stable/c/d136b29bf91dd8e3161281b87de597b7311d9462
      —
      Referenceremoved
      https://git.kernel.org/stable/c/fedeb4468987bcaff85fe3061de5ae052d414740
      —
      Referenceremoved
      https://matrix.tencent.com/en/2026/08/06/sctphantom-CVE-2026-64564
      —

      Source identifier: 416baaa9-dc9f-4396-8d5f-8c081fb06d67

    3. Record modifiedCISA ADP

      CISA assessment (SSVC): exploitation: none known, automatable: yes

      Show the original change
      Individual changes of this event as published by NVD
      TypeActionBeforeAfter
      SSVC assessmentadded
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      {"id":"CVE-2026-64564","role":"CISA Coordinator","options":[{"exploitation":"none"},{"automatable":"yes"},{"technicalImpact":"total"}],"version":"2.0.3","timestamp":"2026-10-16T15:42:57.454548Z"}

      Source identifier: 134c704f-9b21-4f2e-91b3-4a467353bcc0

    4. Record modifiedCVE Program

      Show 12 original changes
      Individual changes of this event as published by NVD
      TypeActionBeforeAfter
      Referenceadded
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      http://www.openwall.com/lists/oss-security/2026/08/06/13
      Referenceadded
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      http://www.openwall.com/lists/oss-security/2026/08/06/3
      Referenceadded
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      http://www.openwall.com/lists/oss-security/2026/08/06/4
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      http://www.openwall.com/lists/oss-security/2026/08/07/1
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      http://www.openwall.com/lists/oss-security/2026/08/07/2
      Referenceadded
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      http://www.openwall.com/lists/oss-security/2026/08/07/8
      Referenceremoved
      http://www.openwall.com/lists/oss-security/2026/08/06/13
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      Referenceremoved
      http://www.openwall.com/lists/oss-security/2026/08/06/3
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      Referenceremoved
      http://www.openwall.com/lists/oss-security/2026/08/06/4
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      Referenceremoved
      http://www.openwall.com/lists/oss-security/2026/08/07/1
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      Referenceremoved
      http://www.openwall.com/lists/oss-security/2026/08/07/2
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      Referenceremoved
      http://www.openwall.com/lists/oss-security/2026/08/07/8
      —

      Source identifier: af854a3a-2127-422b-91ae-364da2661108

    5. Record modifiedLinux

      Show 4 original changes
      Individual changes of this event as published by NVD
      TypeActionBeforeAfter
      Referenceadded
      —
      https://git.kernel.org/stable/c/2b324ba3494ae958cba16a453e3e71489b4de7fc
      Referenceadded
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      https://git.kernel.org/stable/c/a63afa1f9b12d5293cbe0b77fd45dc0632533a13
      Referenceadded
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      https://git.kernel.org/stable/c/a9ce31be4cb1a5dd82b3e0a1d0c3e7cbdcd31293
      Affected versions (publisher)changed
      Linux, Linux
      Linux, Linux

      Source identifier: 416baaa9-dc9f-4396-8d5f-8c081fb06d67

    Show 7 older changes

    1. Record modifiedLinux

      1 individual change: Affected versions (publisher)

      Show the original change
      Individual changes of this event as published by NVD
      TypeActionBeforeAfter
      Affected versions (publisher)changed
      Linux, Linux
      Linux, Linux

      Source identifier: 416baaa9-dc9f-4396-8d5f-8c081fb06d67

    2. Record modifiedLinux

      Show the original change
      Individual changes of this event as published by NVD
      TypeActionBeforeAfter
      Referenceadded
      —
      https://matrix.tencent.com/en/2026/08/06/sctphantom-CVE-2026-64564

      Source identifier: 416baaa9-dc9f-4396-8d5f-8c081fb06d67

    3. Record modifiedLinux

      CVSS V3.1: AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

      Show the original change
      Individual changes of this event as published by NVD
      TypeActionBeforeAfter
      CVSSadded
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      AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

      Source identifier: 416baaa9-dc9f-4396-8d5f-8c081fb06d67

    4. Record modifiedCVE Program

      Show the original change
      Individual changes of this event as published by NVD
      TypeActionBeforeAfter
      Referenceadded
      —
      http://www.openwall.com/lists/oss-security/2026/08/07/8

      Source identifier: af854a3a-2127-422b-91ae-364da2661108

    5. Record modifiedCVE Program

      Show the original change
      Individual changes of this event as published by NVD
      TypeActionBeforeAfter
      Referenceadded
      —
      http://www.openwall.com/lists/oss-security/2026/08/07/1

      Source identifier: af854a3a-2127-422b-91ae-364da2661108

    6. Record modifiedCVE Program

      Show 3 original changes
      Individual changes of this event as published by NVD
      TypeActionBeforeAfter
      Referenceadded
      —
      http://www.openwall.com/lists/oss-security/2026/08/06/13
      Referenceadded
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      http://www.openwall.com/lists/oss-security/2026/08/06/3
      Referenceadded
      —
      http://www.openwall.com/lists/oss-security/2026/08/06/4

      Source identifier: af854a3a-2127-422b-91ae-364da2661108

    7. ReceivedLinux

      Description added or changed

      Show 7 original changes
      Individual changes of this event as published by NVD
      TypeActionBeforeAfter
      Affected versions (publisher)added
      —
      Linux, Linux
      Descriptionadded
      —
      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.
      Referenceadded
      —
      https://git.kernel.org/stable/c/74e8f3e7114f0e26d1b2c4c048044db9fcc27603
      Referenceadded
      —
      https://git.kernel.org/stable/c/85aca407c560aba81b5ce9d3d6cf94c74077d19b
      Referenceadded
      —
      https://git.kernel.org/stable/c/9b2854f86f0b56e9027d68e7a3fc909d1a9b566f
      Referenceadded
      —
      https://git.kernel.org/stable/c/d136b29bf91dd8e3161281b87de597b7311d9462
      Referenceadded
      —
      https://git.kernel.org/stable/c/fedeb4468987bcaff85fe3061de5ae052d414740

      Source identifier: 416baaa9-dc9f-4396-8d5f-8c081fb06d67

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