HighCVE-2026-46306

    Linux Kernel: Denial of Service (CVE-2026-46306)

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

    What is affected, what to do

    A flaw was found in the Linux kernel's flow dissector. This vulnerability allows a remote attacker to cause a Denial of Service (DoS) by sending a specially crafted Point-to-Point Protocol over Ethernet (PPPoE) Protocol Field Compression (PFC) frame to an affected system.

    Update Linux Kernel to version 6.1.175, Linux Kernel to version 6.6.140, Linux Kernel to version 6.12.88.

    Affected
    • Linux Kernel lt 6.0..6.1.175
    • Linux Kernel lt 6.2..6.6.140
    • 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 6.1.175
    • Linux Kernel 6.6.140
    • 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: SUSE, Siemens ProductCERT, Debian LTS, Ubuntu, Red Hat, CVE.org, Msrc Update Guide, BSI

    0.4 %

    EPSS score

    Low — model estimates < 1% exploitation likelihood.

    Source: FIRST EPSS, percentile 38.9

    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
    68.25 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
    0.4 %
    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
    38.9
    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

    A flaw was found in the Linux kernel's flow dissector. This vulnerability allows a remote attacker to cause a Denial of Service (DoS) by sending a specially crafted Point-to-Point Protocol over Ethernet (PPPoE) Protocol Field Compression (PFC) frame to an affected system. The incorrect processing of these compressed frames leads to a memory misalignment, which can result in a kernel crash on certain architectures.

    Source: suse_csaf, siemens_advisory, Debian LTS Advisories, Ubuntu Security Notices, redhat_csaf, NVD (NIST), CVE.org (MITRE), cvelistv5, 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 – < 6.12.88
    • 6.2 – < 6.6.140
    • 6.0 – < 6.1.175
    • 6.19 – < 7.0.7
    • —
    • 6.13 – < 6.18.30
    • 6.12.88
    • 6.6.140
    • 6.1.175
    • 7.0.7
    • 7.1
    • 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
    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 modifiedCISA ADP

      Weakness type: CWE-198

      Show the original change
      Individual changes of this event as published by NVD
      TypeActionBeforeAfter
      Weakness type (CWE)added
      —
      CWE-198

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

    2. 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-2026-46306","role":"CISA Coordinator","options":[{"exploitation":"none"},{"automatable":"yes"},{"technicalImpact":"partial"}],"version":"2.0.3","timestamp":"2026-10-16T15:21:48.023289Z"}

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

    3. Record modifiedSiemens ADP

      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/2026/46xxx/CVE-2026-46306.json">CVE-2026-46306</a>
      Referenceadded
      —
      https://cert-portal.siemens.com/productcert/html/ssa-457936.html
      Referenceadded
      —
      https://cert-portal.siemens.com/productcert/html/ssa-784472.html

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

    4. Record modifiedLinux

      Show 24 original changes
      Individual changes of this event as published by NVD
      TypeActionBeforeAfter
      Referenceadded
      —
      https://git.kernel.org/stable/c/0d00b9015069712944934bab09eaa6c542143049
      Referenceadded
      —
      https://git.kernel.org/stable/c/18ae9eacfc95cc715c0606b2c86e8aa8a86cf3e3
      Referenceadded
      —
      https://git.kernel.org/stable/c/6044392d9cace3a3672b02c8bc7d38b502e51734
      Referenceadded
      —
      https://git.kernel.org/stable/c/7c93f353eab4ea911e394630f07d72e040a729d8
      Referenceadded
      —
      https://git.kernel.org/stable/c/abc5bc84e0f2edc7ea2d437afa6ef3fe1fc43200
      Referenceadded
      —
      https://git.kernel.org/stable/c/d6c19b31a3c1d519fabdcf0aa239e6b6109b9473
      Referenceadded
      —
      https://git.kernel.org/stable/c/db104b0d8a7856397c0469d83a4289adf7c54863
      Referenceadded
      —
      https://git.kernel.org/stable/c/e7c811ca372d53c2be7d01a1614e71fae1054836
      Referenceremoved
      https://git.kernel.org/stable/c/0d00b9015069712944934bab09eaa6c542143049
      —
      Referenceremoved
      https://git.kernel.org/stable/c/18ae9eacfc95cc715c0606b2c86e8aa8a86cf3e3
      —
      Referenceremoved
      https://git.kernel.org/stable/c/6044392d9cace3a3672b02c8bc7d38b502e51734
      —
      Referenceremoved
      https://git.kernel.org/stable/c/7c93f353eab4ea911e394630f07d72e040a729d8
      —
      Referenceremoved
      https://git.kernel.org/stable/c/abc5bc84e0f2edc7ea2d437afa6ef3fe1fc43200
      —
      Referenceremoved
      https://git.kernel.org/stable/c/d6c19b31a3c1d519fabdcf0aa239e6b6109b9473
      —
      Referenceremoved
      https://git.kernel.org/stable/c/db104b0d8a7856397c0469d83a4289adf7c54863
      —
      Referenceremoved
      https://git.kernel.org/stable/c/e7c811ca372d53c2be7d01a1614e71fae1054836
      —
      Reference typeremoved
      https://git.kernel.org/stable/c/0d00b9015069712944934bab09eaa6c542143049 Types: Patch
      —
      Reference typeremoved
      https://git.kernel.org/stable/c/18ae9eacfc95cc715c0606b2c86e8aa8a86cf3e3 Types: Patch
      —
      Reference typeremoved
      https://git.kernel.org/stable/c/6044392d9cace3a3672b02c8bc7d38b502e51734 Types: Patch
      —
      Reference typeremoved
      https://git.kernel.org/stable/c/7c93f353eab4ea911e394630f07d72e040a729d8 Types: Patch
      —
      Reference typeremoved
      https://git.kernel.org/stable/c/abc5bc84e0f2edc7ea2d437afa6ef3fe1fc43200 Types: Patch
      —
      Reference typeremoved
      https://git.kernel.org/stable/c/d6c19b31a3c1d519fabdcf0aa239e6b6109b9473 Types: Patch
      —
      Reference typeremoved
      https://git.kernel.org/stable/c/db104b0d8a7856397c0469d83a4289adf7c54863 Types: Patch
      —
      Reference typeremoved
      https://git.kernel.org/stable/c/e7c811ca372d53c2be7d01a1614e71fae1054836 Types: Patch
      —

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

    5. 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-2026-46306.json">CVE-2026-46306</a>
      Referenceadded
      —
      https://cert-portal.siemens.com/productcert/html/ssa-019113.html

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

    Show one older change

    1. ReceivedLinux

      Description added or changed

      Show 9 original changes
      Individual changes of this event as published by NVD
      TypeActionBeforeAfter
      Descriptionadded
      —
      In the Linux kernel, the following vulnerability has been resolved: flow_dissector: do not dissect PPPoE PFC frames RFC 2516 Section 7 states that Protocol Field Compression (PFC) is NOT RECOMMENDED for PPPoE. In practice, pppd does not support negotiating PFC for PPPoE sessions, and the flow dissector driver has assumed an uncompressed frame until the blamed commit. During the review process of that commit [1], support for PFC is suggested. However, having a compressed (1-byte) protocol field means the subsequent PPP payload is shifted by one byte, causing 4-byte misalignment for the network header and an unaligned access exception on some architectures. The exception can be reproduced by sending a PPPoE PFC frame to an ethernet interface of a MIPS board, with RPS enabled, even if no PPPoE session is active on that interface: $ 0 : 00000000 80c40000 00000000 85144817 $ 4 : 00000008 00000100 80a75758 81dc9bb8 $ 8 : 00000010 8087ae2c 0000003d 00000000 $12 : 000000e0 00000039 00000000 00000000 $16 : 85043240 80a75758 81dc9bb8 00006488 $20 : 0000002f 00000007 85144810 80a70000 $24 : 81d1bda0 00000000 $28 : 81dc8000 81dc9aa8 00000000 805ead08 Hi : 00009d51 Lo : 2163358a epc : 805e91f0 __skb_flow_dissect+0x1b0/0x1b50 ra : 805ead08 __skb_get_hash_net+0x74/0x12c Status: 11000403 KERNEL EXL IE Cause : 40800010 (ExcCode 04) BadVA : 85144817 PrId : 0001992f (MIPS 1004Kc) Call Trace: [<805e91f0>] __skb_flow_dissect+0x1b0/0x1b50 [<805ead08>] __skb_get_hash_net+0x74/0x12c [<805ef330>] get_rps_cpu+0x1b8/0x3fc [<805fca70>] netif_receive_skb_list_internal+0x324/0x364 [<805fd120>] napi_complete_done+0x68/0x2a4 [<8058de5c>] mtk_napi_rx+0x228/0xfec [<805fd398>] __napi_poll+0x3c/0x1c4 [<805fd754>] napi_threaded_poll_loop+0x234/0x29c [<805fd848>] napi_threaded_poll+0x8c/0xb0 [<80053544>] kthread+0x104/0x12c [<80002bd8>] ret_from_kernel_thread+0x14/0x1c Code: 02d51821 1060045b 00000000 <8c640000> 3084000f 2c820005 144001a2 00042080 8e220000 To reduce the attack surface and maintain performance, do not process PPPoE PFC frames. [1] https://lore.kernel.org/r/20220630231016.GA392@debian.home
      Referenceadded
      —
      https://git.kernel.org/stable/c/0d00b9015069712944934bab09eaa6c542143049
      Referenceadded
      —
      https://git.kernel.org/stable/c/18ae9eacfc95cc715c0606b2c86e8aa8a86cf3e3
      Referenceadded
      —
      https://git.kernel.org/stable/c/6044392d9cace3a3672b02c8bc7d38b502e51734
      Referenceadded
      —
      https://git.kernel.org/stable/c/7c93f353eab4ea911e394630f07d72e040a729d8
      Referenceadded
      —
      https://git.kernel.org/stable/c/abc5bc84e0f2edc7ea2d437afa6ef3fe1fc43200
      Referenceadded
      —
      https://git.kernel.org/stable/c/d6c19b31a3c1d519fabdcf0aa239e6b6109b9473
      Referenceadded
      —
      https://git.kernel.org/stable/c/db104b0d8a7856397c0469d83a4289adf7c54863
      Referenceadded
      —
      https://git.kernel.org/stable/c/e7c811ca372d53c2be7d01a1614e71fae1054836

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

    One NVD translation into another language is hidden.

    Linked advisories

    Embed badge

    Show the severity and KEV status of this vulnerability on your site – with a link back here. The image is updated hourly.

    Badge preview for CVE-2026-46306
    <a href="https://intel.neosec.eu/en/cve/CVE-2026-46306"><img src="https://intel.neosec.eu/badge/cve/CVE-2026-46306.svg?lang=en" alt="CVE-2026-46306 – NEOSEC Intel" height="20"></a>