CVE-2026-116542 Netty netty-tcnative before 2.0.84.Final SNI Hostname Spoofing via Modified UTF-8 Decoding

Medium 6.9 Published 26 Oct 2026 Updated 26 Oct 2026

Exploited in the wild: Not known
Fix: None listed

What is CVE-2026-116542?

CVE-2026-116542 is a medium-severity vulnerability in netty-tcnative, published on 26 Oct 2026.

Official description

Netty netty-tcnative before 2.0.84.Final contains an SNI hostname spoofing vulnerability that allows remote unauthenticated clients to alter hostnames via JNI NewStringUTF decoding. Attackers can send overlong encodings like 0xC0 0x80 in the ClientHello server_name to confuse SNI-based certificate selection, access decisions, and logging.

Weakness: CWE-176

Which versions are affected by CVE-2026-116542?

How do I fix CVE-2026-116542?

No fix has been published for CVE-2026-116542 yet. Limit exposure of the affected software until one is available.

Is CVE-2026-116542 being exploited?

There is no known exploitation of CVE-2026-116542 in the wild and no public exploit code.

Sources

Also known as DEBIAN-CVE-2026-116542, GHSA-2784-hxmm-4hgf, GHSA-98m4-7wj9-fxmw, UBUNTU-CVE-2026-116542.