CVE-2026-49423: Remote DOS via uninitialized memory access in KTLS receive
When building the iovec array for a received TLS 1.2 CBC record, ktlsocftlscbcdecrypt() incremented the iovec index for every mbuf in the chain, including mbufs that were skipped because they contained only TLS header bytes. This left uninitialized entries in the iovec array. The iovec array was allocated without zeroing.
A remote TLS peer can cause the kernel to read from uninitialized iovec entries during HMAC computation, resulting in a kernel panic. The peer must be able to control TCP segmentation such that the first mbuf of a CBC record contains only the 5-byte TLS record header.
Affected Software
Event History
Frequently Asked Questions
Which connections are exposed to this issue?
The affected path is KTLS processing of received TLS 1.2 CBC records. A remote TLS peer must be able to send traffic to that KTLS receive path.
What must an attacker control to trigger the panic?
The attacker must control TCP segmentation so that the first mbuf for a CBC record contains only the 5-byte TLS record header. This causes skipped mbufs to leave uninitialized iovec entries that are later read during HMAC computation.