Linux Kernel Vulnerability in AF_PACKET Leading to Zero-Byte Data Transmission Issues

CVE-2026-80742

What is CVE-2026-80742?

A vulnerability was identified in the Linux kernel's AF_PACKET implementation, which allows for the transmission of zero-byte packets through the TPACKET ring buffer. When these packets, characterized by having a length of zero, are sent on devices that do not support hard headers, it could lead to warnings and unintended behavior during the packet transmission process. Specifically, the function tpacket_fill_skb() erroneously populates a socket buffer with a length of zero, subsequently leading to assertions in __dev_queue_xmit(). To mitigate this issue, a return error code of -EINVAL has been introduced to ensure that zero-length packets are rejected in tpacket_snd(), enhancing the robustness of packet handling and preventing potential exploitation.

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