CVE-2024-56636

A flaw was found in the Geneve tunneling implementation of the Linux kernel. In the geneve_xmit_skb() function, the kernel incorrectly assumes that the MAC header is set, leading to invalid memory access when it is not. This issue can be triggered when sending packets through a Geneve tunnel, resulting in warnings or crashes. A local attacker could exploit this by crafting specific network traffic to cause a denial of service, affecting system availability.

The bug could happen when local user sending packet using geneve virtual interfaces that provide Layer 2 Networks over Layer 3 Networks. It doesn't lead to kernel crash, but handled as hardware driver failure that leads to Linux kernel tainted state. The security impact is limited, because no known vector of attack apart from deny of service.

The CVSS score(s) listed for this vulnerability do not reflect the associated product's status, and are included for informational purposes to better understand the severity of this vulnerability.

To mitigate this issue, prevent module geneve from being loaded. Please see https://access.redhat.com/solutions/41278 for how to blacklist a kernel module to prevent it from loading automatically.