CVE-2026-74406: vxlan: Fix potential null-ptr-deref in vxlan_gro_prepare_receive().
In the Linux kernel, the following vulnerability has been resolved:
vxlan: Fix potential null-ptr-deref in vxlangropreparereceive().
udptunnelsockrelease() could set sk->skuserdata to NULL while vxlangropreparereceive() is running.
Let's check if rcudereferenceskuserdata() is NULL after skbgroremcsuminit().
Affected Software
Remediation
Recommended actions to resolve this vulnerability, in priority order.
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ubuntu/linuxto a version that resolves this vulnerability.Fixed in 6.8.0-147.147 - Upgrade
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linux/Kernelto a version that resolves this vulnerability.Fixed in 7.1.5 - Compensating control
In vxlan_gro_prepare_receive(), check whether rcu_dereference_sk_user_data() returns NULL after skb_gro_remcsum_init() before dereferencing it, because udp_tunnel_sock_release() may set sk->sk_user_data to NULL concurrently.
Event History
Frequently Asked Questions
What is the severity of CVE-2026-74406?
CVE-2026-74406 has a risk rating of 19, indicating a high severity vulnerability in the Linux kernel.
How do I fix CVE-2026-74406?
To fix CVE-2026-74406, users should update their Linux kernel to the latest version where the vulnerability has been patched.
What does CVE-2026-74406 affect?
CVE-2026-74406 affects the vxlan implementation in the Linux kernel, specifically related to the vxlan_gro_prepare_receive() function.
What type of vulnerability is CVE-2026-74406?
CVE-2026-74406 is a null pointer dereference vulnerability that can occur during the processing of VXLAN packets.
When was CVE-2026-74406 published?
CVE-2026-74406 was published on August 15, 2026.