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PatchSiren cyber security CVE debrief

CVE-2026-90105 Linux CVE debrief

A vulnerability in the Linux kernel's vxlan implementation could allow an attacker to read neigh ha data partially while it is being updated. The issue arises from the use of arp/neigh_reduce to read neigh ha directly. To address this, the neigh_ha_snapshot function is used to take a stable snapshot of the address. This vulnerability affects Linux kernel developers and administrators who should assess exposure and apply patches to prevent partial reads of neigh ha data. The CVE record and source item provide information on the vulnerability and its resolution in the Linux kernel.

Vendor
Linux
Product
Unknown
CVSS
Unknown
CISA KEV
Not listed in stored evidence
Original CVE published
2026-09-17
Original CVE updated
2026-10-19
Advisory published
2026-09-17
Advisory updated
2026-10-19

Who should care

Linux kernel developers and administrators should assess exposure and apply patches to prevent partial reads of neigh ha data. They should review compensating controls for exposed systems while remediation is scheduled and verified, and check relevant monitoring, detection, and logs for exposed assets that need extra review.

Why it matters

A vulnerability in the Linux kernel's vxlan implementation could allow an attacker to read neigh ha data partially while it is being updated.

  • Verify Linux kernel versions and apply patches to prevent partial reads of neigh ha data.
  • Use neigh_ha_snapshot to take a stable snapshot of the address.
  • Monitor Linux kernel updates for potential security patches.

Technical summary

The Linux kernel's vxlan implementation has a vulnerability that could allow an attacker to read neigh ha data partially while it is being updated. The issue arises from the use of arp/neigh_reduce to read neigh ha directly. To address this, the neigh_ha_snapshot function is used to take a stable snapshot of the address. This vulnerability affects Linux kernel developers and administrators who should assess exposure and apply patches to prevent partial reads of neigh ha data. The CVE record and source item provide information on the vulnerability and its resolution in the Linux kernel.

Defensive priority

Verify Linux kernel versions and apply patches to prevent partial reads of neigh ha data.

Recommended defensive actions

  • Verify Linux kernel versions and apply patches to prevent partial reads of neigh ha data.
  • Use neigh_ha_snapshot to take a stable snapshot of the address.
  • Monitor Linux kernel updates for potential security patches.
  • Review compensating controls for exposed systems while remediation is scheduled and verified.
  • Check relevant monitoring, detection, and logs for exposed assets that need extra review.
  • Track exceptions, retest remediated assets, and close the item only after evidence is documented.
  • Confirm whether affected product deployments exist in managed environments and assign an owner for follow-up.

Evidence notes

The CVE record and source item provide information on the vulnerability and its resolution in the Linux kernel. The issue is related to the vxlan implementation and the use of neigh_ha_snapshot to take a stable snapshot of the address.

Sources and references

Verified primary and authoritative sources

  • CVE-2026-90105 CVE Program record

    Publisher, destination, and source semantics verified

    URL: https://www.cve.org/CVERecord?id=CVE-2026-90105

    CVE Program - Official CVE Program record with source-provided CVE metadata.

  • CVE-2026-90105 NVD vulnerability detail

    Publisher, destination, and source semantics verified

    URL: https://nvd.nist.gov/vuln/detail/CVE-2026-90105

    NIST National Vulnerability Database - Official NIST NVD detail page and source-specific vulnerability assessment.

Supplemental references

  • vxlan: fix reading neigh ha

    Unverified legacy reference

    URL: https://raw.githubusercontent.com/CVEProject/cvelistV5/main/cves/2026/90xxx/CVE-2026-90105.json

    cve_program_cvelist_v5

  • Source reference

    Unverified legacy reference

    URL: https://git.kernel.org/stable/c/f43ef9a3f9c121472a0754c9e9bff13317ace0f7

    Supplemental source

  • Source reference

    Unverified legacy reference

    URL: https://git.kernel.org/stable/c/ecc8bac11a101e5f6989a14b92e17b51f9761630

    Supplemental source

  • Source reference

    Unverified legacy reference

    URL: https://git.kernel.org/stable/c/b824059a673b2283e78c7aae2c7d257aad7f0e1d

    Supplemental source

Methodology and review provenance

AI-assisted synthesis based on stored public vulnerability evidence. System validation, approval state, and publication status do not by themselves establish human review of this revision. PatchSiren helps prioritize defensive review and does not prove exposure or remediation on any system.