Linux Kernel up to 6.18.1 net vxlan_xmit_one null pointer dereference

Summaryinfo

A vulnerability was found in Linux Kernel up to 6.18.1 and classified as critical. This affects the function vxlan_xmit_one of the component net. Such manipulation leads to null pointer dereference. This vulnerability is uniquely identified as CVE-2025-68353. No exploit exists. It is suggested to upgrade the affected component.

Detailsinfo

A vulnerability was found in Linux Kernel up to 6.18.1. It has been rated as critical. Affected by this issue is the function vxlan_xmit_one of the component net. The manipulation with an unknown input leads to a null pointer dereference vulnerability. Using CWE to declare the problem leads to CWE-476. A NULL pointer dereference occurs when the application dereferences a pointer that it expects to be valid, but is NULL, typically causing a crash or exit. Impacted is availability. CVE summarizes:

In the Linux kernel, the following vulnerability has been resolved: net: vxlan: prevent NULL deref in vxlan_xmit_one Neither sock4 nor sock6 pointers are guaranteed to be non-NULL in vxlan_xmit_one, e.g. if the iface is brought down. This can lead to the following NULL dereference: BUG: kernel NULL pointer dereference, address: 0000000000000010 Oops: Oops: 0000 [#1] SMP NOPTI RIP: 0010:vxlan_xmit_one+0xbb3/0x1580 Call Trace: vxlan_xmit+0x429/0x610 dev_hard_start_xmit+0x55/0xa0 __dev_queue_xmit+0x6d0/0x7f0 ip_finish_output2+0x24b/0x590 ip_output+0x63/0x110 Mentioned commits changed the code path in vxlan_xmit_one and as a side effect the sock4/6 pointer validity checks in vxlan(6)_get_route were lost. Fix this by adding back checks. Since both commits being fixed were released in the same version (v6.7) and are strongly related, bundle the fixes in a single commit.

The advisory is available at git.kernel.org. This vulnerability is handled as CVE-2025-68353 since 12/16/2025. The exploitation is known to be difficult. Technical details are known, but there is no available exploit.

The vulnerability scanner Nessus provides a plugin with the ID 279713 (Linux Distros Unpatched Vulnerability : CVE-2025-68353), which helps to determine the existence of the flaw in a target environment.

Upgrading to version 6.18.2 or 6.19-rc1 eliminates this vulnerability. Applying the patch 4ac26aafdc8c7271414e2e7c0b2cb266a26591bc/1f73a56f986005f0bc64ed23873930e2ee4f5911 is able to eliminate this problem. The bugfix is ready for download at git.kernel.org. The best possible mitigation is suggested to be upgrading to the latest version.

The vulnerability is also documented in the databases at Tenable (279713) and CERT Bund (WID-SEC-2025-2920). If you want to get best quality of vulnerability data, you may have to visit VulDB.

Affected

• Open Source Linux Kernel

Productinfo

Type

• Operating System

Vendor

• Linux

Name

• Kernel

Version

• 6.18.0
• 6.18.1

License

• open-source

Website

• Vendor: https://www.kernel.org/

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Entryinfo

If you want to get best quality of vulnerability data, you may have to visit VulDB.

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