HighCVE-2026-46110

    Linux Kernel: security vulnerability (CVE-2026-46110)

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

    What is affected, what to do

    Update Linux Kernel to version 6.1.176, Linux Kernel to version 6.6.140, Linux Kernel to version 6.6.

    Affected
    • Linux Kernel lt 6.1.64..6.1.176
    • Linux Kernel lt 6.6.3..6.6.140
    • Linux Kernel lt 6.5.13..6.6
    • Linux Kernel lt 6.7..6.12.88
    • Linux Kernel lt 6.13..6.18.30
    • Linux Kernel lt 6.19..7.0.7
    Fixed in
    • Linux Kernel 6.1.176
    • Linux Kernel 6.6.140
    • Linux Kernel 6.6
    • Linux Kernel 6.12.88
    • Linux Kernel 6.18.30
    • Linux Kernel 7.0.7
    • Linux Kernel 7.1

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

    Metrics

    7.5

    Priority

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

    Source: Vendor (CNA), CVSS v3

    7.5

    CVSS v3

    Severity High on the scale from 0 to 10.

    Source: Debian LTS, SUSE, Ubuntu, Siemens ProductCERT, CVE.org, Msrc Update Guide, EUVD, BSI

    0.5 %

    EPSS score

    Low — model estimates < 1% exploitation likelihood.

    Source: FIRST EPSS, percentile 43.6

    Show all metrics
    Severity
    High
    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
    70.70 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
    7.5 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
    7.5
    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
    0.5 %
    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
    43.6
    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:

    net: stmmac: Prevent NULL deref when RX memory exhausted

    The CPU receives frames from the MAC through conventional DMA: the CPU allocates buffers for the MAC, then the MAC fills them and returns ownership to the CPU. For each hardware RX queue, the CPU and MAC coordinate through a shared ring array of DMA descriptors: one descriptor per DMA buffer. Each descriptor includes the buffer's physical address and a status flag ("OWN") indicating which side owns the buffer: OWN=0 for CPU, OWN=1 for MAC. The CPU is only allowed to set the flag and the MAC is only allowed to clear it, and both must move through the ring in sequence: thus the ring is used for both "submissions" and "completions."

    In the stmmac driver, stmmac_rx() bookmarks its position in the ring with the cur_rx index. The main receive loop in that function checks for rx_descs[cur_rx].own=0, gives the corresponding buffer to the network stack (NULLing the pointer), and increments cur_rx modulo the ring size. After the loop exits, stmmac_rx_refill(), which bookmarks its position with dirty_rx, allocates fresh buffers and rearms the descriptors (setting OWN=1). If it fails any allocation, it simply stops early (leaving OWN=0) and will retry where it left off when next called.

    This means descriptors have a three-stage lifecycle (terms my own):

    • empty (OWN=1, buffer valid)
    • full (OWN=0, buffer valid and populated)
    • dirty (OWN=0, buffer NULL)

    But because stmmac_rx() only checks OWN, it confuses full/dirty. In the past (see 'Fixes:'), there was a bug where the loop could cycle cur_rx all the way back to the first descriptor it dirtied, resulting in a NULL dereference when mistaken for full. The aforementioned commit resolved that specific failure by capping the loop's iteration limit at dma_rx_size - 1, but this is only a partial fix: if the previous stmmac_rx_refill() didn't complete, then there are leftover dirty descriptors that the loop might encounter without needing to cycle fully around. The current code therefore panics (see 'Closes:') when stmmac_rx_refill() is memory-starved long enough for cur_rx to catch up to dirty_rx.

    Fix this by explicitly checking, before advancing cur_rx, if the next entry is dirty; exit the loop if so. This prevents processing of the final, used descriptor until stmmac_rx_refill() succeeds, but fully prevents the cur_rx == dirty_rx ambiguity as the previous bugfix intended: so remove the clamp as well. Since stmmac_rx_zc() is a copy-paste-and-tweak of stmmac_rx() and the code structure is identical, any fix to stmmac_rx() will also need a corresponding fix for stmmac_rx_zc(). Therefore, apply the same check there.

    In stmmac_rx() (not stmmac_rx_zc()), a related bug remains: after the MAC sets OWN=0 on the final descriptor, it will be unable to send any further DMA-complete IRQs until it's given more empty descriptors. Currently, the driver simply hopes that the next stmmac_rx_refill() succeeds, risking an indefinite stall of the receive process if not. But this is not a regression, so it can be addressed in a future change.

    Source: Debian LTS Advisories, suse_csaf, Ubuntu Security Notices, siemens_advisory, cvelistv5, Microsoft Security Update Guide, ENISA EUVD, NVD (NIST), 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 – < 6.12.88
    • 6.1.64 – < 6.1.176
    • 6.19 – < 7.0.7
    • —
    • 6.5.13 – < 6.6
    • 6.6.3 – < 6.6.140
    • 6.13 – < 6.18.30
    • 6.12.88
    • 6.1.176
    • 7.0.7
    • 7.1
    • 6.6
    • 6.6.140
    • 6.18.30
    SiemensSIMATIC S7
    • 1500 TM MFP V1.1.1 GNU/Linux subsystem
    • —

    Vendors and products

    Affected operating systems

    Affected operating systems
    Linuxdebianlinuxbookworm
    Linuxdebianlinux-6.1bullseye
    Linuxubuntulinux-oracle-7.0noble
    Linuxlinuxlinux_kernel6.7
    Linuxlinuxlinux_kernel7.1
    Linuxlinuxlinux_kernel—

    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 modifiedSiemens ADP

      Show 2 original changes
      Individual changes of this event as published by NVD
      TypeActionBeforeAfter
      Affected versions (publisher)added
      —
      New affected value received. <a href="https://github.com/CVEProject/cvelistV5/blob/main/cves/2026/46xxx/CVE-2026-46110.json">CVE-2026-46110</a>
      Referenceadded
      —
      https://cert-portal.siemens.com/productcert/html/ssa-784472.html

      Source identifier: 0b142b55-0307-4c5a-b3c9-f314f3fb7c5e

    2. Record modifiedLinux

      Show 18 original changes
      Individual changes of this event as published by NVD
      TypeActionBeforeAfter
      Referenceadded
      —
      https://git.kernel.org/stable/c/0bb05e6adfa99a2ea1fee1125cc0953409f83ed8
      Referenceadded
      —
      https://git.kernel.org/stable/c/4af2e62cbcda575a174acd230c3f3a208135e16d
      Referenceadded
      —
      https://git.kernel.org/stable/c/5c910f7708e3c507b037ca91ca5b09f8cfe71e65
      Referenceadded
      —
      https://git.kernel.org/stable/c/950cb436165aad0f8f2cd49da3cd07677465bcde
      Referenceadded
      —
      https://git.kernel.org/stable/c/e1c50b273298c7cd9b08b113e7a7598b531a02f5
      Referenceadded
      —
      https://git.kernel.org/stable/c/fdeb95b1fc7de25c9362990efb9996a8d761055c
      Referenceremoved
      https://git.kernel.org/stable/c/0bb05e6adfa99a2ea1fee1125cc0953409f83ed8
      —
      Referenceremoved
      https://git.kernel.org/stable/c/4af2e62cbcda575a174acd230c3f3a208135e16d
      —
      Referenceremoved
      https://git.kernel.org/stable/c/5c910f7708e3c507b037ca91ca5b09f8cfe71e65
      —
      Referenceremoved
      https://git.kernel.org/stable/c/950cb436165aad0f8f2cd49da3cd07677465bcde
      —
      Referenceremoved
      https://git.kernel.org/stable/c/e1c50b273298c7cd9b08b113e7a7598b531a02f5
      —
      Referenceremoved
      https://git.kernel.org/stable/c/fdeb95b1fc7de25c9362990efb9996a8d761055c
      —
      Reference typeremoved
      https://git.kernel.org/stable/c/0bb05e6adfa99a2ea1fee1125cc0953409f83ed8 Types: Patch
      —
      Reference typeremoved
      https://git.kernel.org/stable/c/4af2e62cbcda575a174acd230c3f3a208135e16d Types: Patch
      —
      Reference typeremoved
      https://git.kernel.org/stable/c/5c910f7708e3c507b037ca91ca5b09f8cfe71e65 Types: Patch
      —
      Reference typeremoved
      https://git.kernel.org/stable/c/950cb436165aad0f8f2cd49da3cd07677465bcde Types: Patch
      —
      Reference typeremoved
      https://git.kernel.org/stable/c/e1c50b273298c7cd9b08b113e7a7598b531a02f5 Types: Patch
      —
      Reference typeremoved
      https://git.kernel.org/stable/c/fdeb95b1fc7de25c9362990efb9996a8d761055c Types: Patch
      —

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

    3. Record modifiedLinux

      Show 2 original changes
      Individual changes of this event as published by NVD
      TypeActionBeforeAfter
      Referenceadded
      —
      https://git.kernel.org/stable/c/fdeb95b1fc7de25c9362990efb9996a8d761055c
      Affected versions (publisher)changed
      Linux, Linux
      Linux, Linux

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

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