CriticalCVE-2026-43083

    Linux Kernel: Out-of-bounds Read (CVE-2026-43083)

    Published Last modified Sources: SUSE, Ubuntu, CVE.org, Msrc Update Guide, EUVD, BSI

    What is affected, what to do

    In the Linux kernel, the following vulnerability has been resolved: net: ioam6: fix OOB and missing lock When trace->type.bit6 is set: if (trace->type.bit6) { ... queue = skb_get_tx_queue(dev, skb); qdisc = rcu_dereference(queue->qdisc); This code can lead to an out-of-bounds access of the dev->_tx[] array when is_input is true. In such a case, the packet is on the RX path and skb->queue_mapping contains the RX queue index of the ingress device.

    Update Linux Kernel to version 6.6.160, Linux Kernel to version 6.12.114, Linux Kernel to version 6.18.24.

    Affected
    • Linux Kernel lt 5.17..6.6.160
    • Linux Kernel lt 6.7..6.12.114
    • Linux Kernel lt 6.13..6.18.24
    • Linux Kernel lt 6.19..6.19.14
    • Linux Kernel lt 6.20..7.0
    Fixed in
    • Linux Kernel 6.6.160
    • Linux Kernel 6.12.114
    • Linux Kernel 6.18.24
    • Linux Kernel 6.19.14
    • Linux Kernel 7.0

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    Metrics

    9.1

    Priority

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

    Source: Vendor (CNA), CVSS v3

    9.1

    CVSS v3

    Severity Critical on the scale from 0 to 10.

    Source: SUSE, Ubuntu, CVE.org, Msrc Update Guide, EUVD, BSI

    0.6 %

    EPSS score

    Low — model estimates < 1% exploitation likelihood.

    Source: FIRST EPSS, percentile 46.3

    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
    79.80 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
    no public PoC known
    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
    9.1 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
    9.1
    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
    0.6 %
    Low — model estimates < 1% 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
    46.3
    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
    CWE

    CWE is a catalogue of typical weakness types in software and hardware — such as flawed input validation, unsafe memory handling or poor authentication. Where a CVE names a concrete vulnerability in a concrete product, a CWE describes the underlying class of defect.

    Read in glossary
    CWE-125, CWE-125

    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: net: ioam6: fix OOB and missing lock When trace->type.bit6 is set: if (trace->type.bit6) { ... queue = skb_get_tx_queue(dev, skb); qdisc = rcu_dereference(queue->qdisc); This code can lead to an out-of-bounds access of the dev->_tx[] array when is_input is true. In such a case, the packet is on the RX path and skb->queue_mapping contains the RX queue index of the ingress device. If the ingress device has more RX queues than the egress device (dev) has TX queues, skb_get_queue_mapping(skb) will exceed dev->num_tx_queues. Add a check to avoid this situation since skb_get_tx_queue() does not clamp the index. This issue has also revealed that per queue visibility cannot be accurate and will be replaced later as a new feature. While at it, add missing lock around qdisc_qstats_qlen_backlog(). The function __ioam6_fill_trace_data() is called from both softirq and process contexts, hence the use of spin_lock_bh() here.

    Source: suse_csaf, Ubuntu Security Notices, NVD (NIST), cvelistv5, Microsoft Security Update Guide, ENISA EUVD, CVE.org (MITRE), 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 – < 6.12.114
    • 6.19 – < 6.19.14
    • 6.13 – < 6.18.24
    • 5.17 – < 6.6.160
    • 6.20 – < 7.0
    • 6.12.114
    • 6.19.14
    • 6.18.24
    • 6.6.160
    • 7.0
    MicrosoftAzure Linux
    • azl3
    • —

    Vendors and products

    Affected operating systems

    Affected operating systems
    Linuxlinuxlinux_kernel7.0
    Linuxlinuxlinux_kernel—

    Weakness classes (CWE)

    • CWE-125Out-of-bounds Read

      Base

      The product reads data past the end, or before the beginning, of the intended buffer.

      Entry at MITRE CWE-125

    • CWE-125Out-of-bounds Read

      Base

      The product reads data past the end, or before the beginning, of the intended buffer.

      Entry at MITRE CWE-125

    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 modifiedLinux

      Show 3 original changes
      Individual changes of this event as published by NVD
      TypeActionBeforeAfter
      Affected versions (publisher)added
      —
      Affected value modified. <a href="https://github.com/CVEProject/cvelistV5/blob/main/cves/2026/43xxx/CVE-2026-43083.json">CVE-2026-43083</a>
      Referenceadded
      —
      https://git.kernel.org/stable/c/a05a85779c2574b6534abb8cdc6d65fbc2e91208
      Referenceadded
      —
      https://git.kernel.org/stable/c/f1af9d19503b73011dae5051c354fd39b03e240d

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

    2. Record modifiedCISA ADP

      Weakness type: CWE-125

      Show the original change
      Individual changes of this event as published by NVD
      TypeActionBeforeAfter
      Weakness type (CWE)added
      —
      CWE-125

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

    3. Record modifiedLinux

      Show 9 original changes
      Individual changes of this event as published by NVD
      TypeActionBeforeAfter
      Referenceadded
      —
      https://git.kernel.org/stable/c/6d1d9ed9b409e0662241e3d245d574a18f643494
      Referenceadded
      —
      https://git.kernel.org/stable/c/95a1334748c95dd15546056280ade0c4b8dd7b78
      Referenceadded
      —
      https://git.kernel.org/stable/c/b30b1675aa2bcf0491fd3830b051df4e08a7c8ca
      Referenceremoved
      https://git.kernel.org/stable/c/6d1d9ed9b409e0662241e3d245d574a18f643494
      —
      Referenceremoved
      https://git.kernel.org/stable/c/95a1334748c95dd15546056280ade0c4b8dd7b78
      —
      Referenceremoved
      https://git.kernel.org/stable/c/b30b1675aa2bcf0491fd3830b051df4e08a7c8ca
      —
      Reference typeremoved
      https://git.kernel.org/stable/c/6d1d9ed9b409e0662241e3d245d574a18f643494 Types: Patch
      —
      Reference typeremoved
      https://git.kernel.org/stable/c/95a1334748c95dd15546056280ade0c4b8dd7b78 Types: Patch
      —
      Reference typeremoved
      https://git.kernel.org/stable/c/b30b1675aa2bcf0491fd3830b051df4e08a7c8ca Types: Patch
      —

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

    4. 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
      —
      {"id":"CVE-2026-43083","role":"CISA Coordinator","options":[{"exploitation":"none"},{"automatable":"yes"},{"technicalImpact":"partial"}],"version":"2.0.3","timestamp":"2026-10-16T15:14:26.779582Z"}

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

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