FreeBSD ktls: Uninitialized iovec in TLS 1.2 CBC causes kernel panic
CVE-2026-49423 Published on August 19, 2026
Remote DOS via uninitialized memory access in KTLS receive
When building the iovec array for a received TLS 1.2 CBC record, ktls_ocf_tls_cbc_decrypt() 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.
Weakness Type
Use of Uninitialized Resource
The software uses or accesses a resource that has not been initialized. When a resource has not been properly initialized, the software may behave unexpectedly. This may lead to a crash or invalid memory access, but the consequences vary depending on the type of resource and how it is used within the software.
Products Associated with CVE-2026-49423
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Affected Versions
FreeBSD:- Version 15.1-RELEASE and below p1 is affected.
- Version 15.0-RELEASE and below p11 is affected.
- Version 14.4-RELEASE and below p7 is affected.
- Version 14.3-RELEASE and below p16 is affected.