Linux Kernel up to 7.2.5 vxlan arp/neigh_reduce race condition

Summaryinfo

A vulnerability identified as very critical has been detected in Linux Kernel up to 7.2.5. The impacted element is the function arp/neigh_reduce of the component vxlan. Performing a manipulation results in race condition. This vulnerability is identified as CVE-2026-90105. The attack can be initiated remotely. There is not any exploit available. You should upgrade the affected component.

Detailsinfo

A vulnerability classified as very critical has been found in Linux Kernel up to 7.2.5. This affects the function arp/neigh_reduce of the component vxlan. The manipulation with an unknown input leads to a race condition vulnerability. CWE is classifying the issue as CWE-362. The product contains a code sequence that can run concurrently with other code, and the code sequence requires temporary, exclusive access to a shared resource, but a timing window exists in which the shared resource can be modified by another code sequence that is operating concurrently. This is going to have an impact on confidentiality, integrity, and availability. The summary by CVE is:

In the Linux kernel, the following vulnerability has been resolved: vxlan: fix reading neigh ha Currently arp/neigh_reduce read neigh ha directly which can lead to partial reads while the neigh is being updated. Use neigh_ha_snapshot to take a stable snapshot of the address similar to route_shortcircuit which already does the right thing.

It is possible to read the advisory at git.kernel.org. This vulnerability is uniquely identified as CVE-2026-90105 since 09/11/2026. The exploitability is told to be easy. It is possible to initiate the attack remotely. No form of authentication is needed for exploitation. Technical details of the vulnerability are known, but there is no available exploit. The pricing for an exploit might be around USD $0-$5k at the moment (estimation calculated on 09/17/2026).

Upgrading to version 7.2.6 or 7.3-rc1 eliminates this vulnerability. Applying the patch ecc8bac11a101e5f6989a14b92e17b51f9761630/b824059a673b2283e78c7aae2c7d257aad7f0e1d is able to eliminate this problem. The best possible mitigation is suggested to be upgrading to the latest version.

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Productinfo

Type

• Operating System

Vendor

• Linux

Name

• Kernel

Version

• 7.2.0
• 7.2.1
• 7.2.2
• 7.2.3
• 7.2.4
• 7.2.5

License

• open-source

Website

• Vendor: https://www.kernel.org/

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