HighCVE-2026-23310

    Linux Kernel: security vulnerability (CVE-2026-23310)

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

    What is affected, what to do

    Update Linux Kernel to version 6.1.176, Linux Kernel to version 6.6.130, Linux Kernel to version 6.12.77.

    Affected
    • Linux Kernel lt 5.15..6.1.176
    • Linux Kernel lt 6.2..6.6.130
    • Linux Kernel lt 6.7..6.12.77
    • Linux Kernel lt 6.13..6.18.17
    • Linux Kernel lt 6.19..6.19.7
    • Linux Kernel lt 6.20..7.0
    Fixed in
    • Linux Kernel 6.1.176
    • Linux Kernel 6.6.130
    • Linux Kernel 6.12.77
    • Linux Kernel 6.18.17
    • Linux Kernel 6.19.7
    • Linux Kernel 7.0

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

    Metrics

    7.1

    Priority

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

    Source: Vendor (CNA), CVSS v3

    5.5

    CVSS v3

    Severity Medium on the scale from 0 to 10.

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

    0.1 %

    EPSS score

    Low — model estimates < 1% exploitation likelihood.

    Source: FIRST EPSS, percentile 2.4

    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
    43.03 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
    7.1 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
    5.5
    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
    0.1 %
    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
    2.4
    Low — this CVE sits in the lower 10% of all CVEs scored today.
    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:

    bpf/bonding: reject vlan+srcmac xmit_hash_policy change when XDP is loaded

    bond_option_mode_set() already rejects mode changes that would make a loaded XDP program incompatible via bond_xdp_check(). However, bond_option_xmit_hash_policy_set() has no such guard.

    For 802.3ad and balance-xor modes, bond_xdp_check() returns false when xmit_hash_policy is vlan+srcmac, because the 802.1q payload is usually absent due to hardware offload. This means a user can:

    1. Attach a native XDP program to a bond in 802.3ad/balance-xor mode with a compatible xmit_hash_policy (e.g. layer2+3).
    2. Change xmit_hash_policy to vlan+srcmac while XDP remains loaded.

    This leaves bond->xdp_prog set but bond_xdp_check() now returning false for the same device. When the bond is later destroyed, dev_xdp_uninstall() calls bond_xdp_set(dev, NULL, NULL) to remove the program, which hits the bond_xdp_check() guard and returns -EOPNOTSUPP, triggering:

    WARN_ON(dev_xdp_install(dev, mode, bpf_op, NULL, 0, NULL))

    Fix this by rejecting xmit_hash_policy changes to vlan+srcmac when an XDP program is loaded on a bond in 802.3ad or balance-xor mode.

    commit 39a0876d595b ("net, bonding: Disallow vlan+srcmac with XDP") introduced bond_xdp_check() which returns false for 802.3ad/balance-xor modes when xmit_hash_policy is vlan+srcmac. The check was wired into bond_xdp_set() to reject XDP attachment with an incompatible policy, but the symmetric path -- preventing xmit_hash_policy from being changed to an incompatible value after XDP is already loaded -- was left unguarded in bond_option_xmit_hash_policy_set().

    Note: commit 094ee6017ea0 ("bonding: check xdp prog when set bond mode") later added a similar guard to bond_option_mode_set(), but bond_option_xmit_hash_policy_set() remained unprotected.

    Source: Debian Security Advisories, Debian LTS Advisories, siemens_advisory, Ubuntu Security Notices, BSI WID Portal, BSI CSAF, cvelistv5, NVD (NIST), Microsoft Security Update Guide, CVE.org (MITRE), ENISA EUVD

    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 – < 6.12.77
    • 6.2 – < 6.6.130
    • 6.20 – < 7.0
    • 5.15 – < 6.1.176
    • 6.19 – < 6.19.7
    • 6.13 – < 6.18.17
    • 6.12.77
    • 6.6.130
    • 7.0
    • 6.1.176
    • 6.19.7
    • 6.18.17
    SiemensSIMATIC S7
    • 1500 TM MFP V1.1.1 GNU/Linux subsystem
    • —

    Vendors and products

    Affected operating systems

    Affected operating systems
    Linuxdebianlinuxbookworm
    Linuxdebianlinuxtrixie
    Linuxdebianlinux-6.1bullseye
    Linuxlinuxlinux_kernel7.0
    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 modifiedLinux

      Show 17 original changes
      Individual changes of this event as published by NVD
      TypeActionBeforeAfter
      Referenceadded
      —
      https://git.kernel.org/stable/c/0a80e6ecaf669c77260b44254f4a84d76bf83e89
      Referenceadded
      —
      https://git.kernel.org/stable/c/0ace8027e41f6f094ef6c1aca42d2ed6cd7af54e
      Referenceadded
      —
      https://git.kernel.org/stable/c/479d589b40b836442bbdadc3fdb37f001bb67f26
      Referenceadded
      —
      https://git.kernel.org/stable/c/5c262bd0e39320a6d6c8277cb8349ce21c01b8c1
      Referenceadded
      —
      https://git.kernel.org/stable/c/d36ad7e126c6a0c5f699583309ccc37e3a3263ea
      Referenceadded
      —
      https://git.kernel.org/stable/c/e85fa809e507b9d8eff4840888b8c727e4e8448c
      Referenceremoved
      https://git.kernel.org/stable/c/0a80e6ecaf669c77260b44254f4a84d76bf83e89
      —
      Referenceremoved
      https://git.kernel.org/stable/c/0ace8027e41f6f094ef6c1aca42d2ed6cd7af54e
      —
      Referenceremoved
      https://git.kernel.org/stable/c/479d589b40b836442bbdadc3fdb37f001bb67f26
      —
      Referenceremoved
      https://git.kernel.org/stable/c/5c262bd0e39320a6d6c8277cb8349ce21c01b8c1
      —
      Referenceremoved
      https://git.kernel.org/stable/c/d36ad7e126c6a0c5f699583309ccc37e3a3263ea
      —
      Referenceremoved
      https://git.kernel.org/stable/c/e85fa809e507b9d8eff4840888b8c727e4e8448c
      —
      Reference typeremoved
      https://git.kernel.org/stable/c/0ace8027e41f6f094ef6c1aca42d2ed6cd7af54e Types: Patch
      —
      Reference typeremoved
      https://git.kernel.org/stable/c/479d589b40b836442bbdadc3fdb37f001bb67f26 Types: Patch
      —
      Reference typeremoved
      https://git.kernel.org/stable/c/5c262bd0e39320a6d6c8277cb8349ce21c01b8c1 Types: Patch
      —
      Reference typeremoved
      https://git.kernel.org/stable/c/d36ad7e126c6a0c5f699583309ccc37e3a3263ea Types: Patch
      —
      Reference typeremoved
      https://git.kernel.org/stable/c/e85fa809e507b9d8eff4840888b8c727e4e8448c Types: Patch
      —

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

    2. 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/2026/23xxx/CVE-2026-23310.json">CVE-2026-23310</a>
      Referenceadded
      —
      https://cert-portal.siemens.com/productcert/html/ssa-784472.html

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

    3. Record modifiedLinux

      Show 2 original changes
      Individual changes of this event as published by NVD
      TypeActionBeforeAfter
      Referenceadded
      —
      https://git.kernel.org/stable/c/0a80e6ecaf669c77260b44254f4a84d76bf83e89
      Affected versions (publisher)changed
      Linux, Linux
      Linux, Linux

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

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