CVE-2026-31738 vxlan: validate ND option lengths in vxlan_na_create
A malformed VXLAN ND option can cause out-of-bounds reads or writes in the Linux kernel, potentially leading to crashes or code execution.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Local or same network only
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-31738?
CVE-2026-31738 is a medium-severity memory corruption vulnerability in Linux kernel, published on 1 May 2026. It can only be exploited from the same machine or local network, with no action from the victim.
Official description
In the Linux kernel, the following vulnerability has been resolved:
vxlan: validate ND option lengths in vxlan_na_create
vxlan_na_create() walks ND options according to option-provided lengths. A malformed option can make the parser advance beyond the computed option span or use a too-short source LLADDR option payload.
Validate option lengths against the remaining NS option area before advancing, and only read source LLADDR when the option is large enough for an Ethernet address.
Which versions are affected by CVE-2026-31738?
It affects 1 product.
Products include Linux kernel.
How do I fix CVE-2026-31738?
Apply the vendor's patch.
Upgrade to the fixed version. Memory-safe languages, compiler hardening and fuzzing prevent most new cases. More about Memory corruption.
Is CVE-2026-31738 being exploited?
There is no known exploitation of CVE-2026-31738 in the wild and no public exploit code.
Other vulnerabilities in Linux kernel
Sources
Also known as BELL-CVE-2026-31738, DEBIAN-CVE-2026-31738, GHSA-7cj7-4x33-pjx2, ROOT-OS-DEBIAN-11-CVE-2026-31738, ROOT-OS-UBUNTU-2204-CVE-2026-31738, ROOT-OS-UBUNTU-2404-CVE-2026-31738 and 1 more.