CVE-2026-49423 Remote DOS via uninitialized memory access in KTLS receive
A remote attacker can cause a kernel panic in FreeBSD by triggering uninitialized memory access during TLS record processing.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Local or same network only
- Victim action needed
- Not needed
- Fix
- None listed
What is CVE-2026-49423?
CVE-2026-49423 is a low-severity vulnerability in Freebsd Freebsd, published on 19 Aug 2026. It can only be exploited from the same machine or local network, with no action from the victim.
Official description
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: CWE-908
Which versions are affected by CVE-2026-49423?
It affects 1 product.
Products include Freebsd Freebsd.
How do I fix CVE-2026-49423?
No fix has been published for CVE-2026-49423 yet. Limit exposure of the affected software until one is available.
Is CVE-2026-49423 being exploited?
There is no known exploitation of CVE-2026-49423 in the wild and no public exploit code.
Other vulnerabilities in Freebsd Freebsd
Sources
Also known as GHSA-c5hg-f3pf-qgxh.