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.
Affected products
| Vendor | Product | Affected | Fixed |
|---|---|---|---|
| netty | netty-tcnative | < 2.0.84.Final | 2.0.84.Final |
| netty | netty-tcnative-boringssl-static | < 2.0.84.Final | 2.0.84.Final |
Fixed in Linux distributions
Distributions backport fixes, so the version that fixes this vulnerability differs per release — upgrade to at least the version shown. From the distributions' security trackers and advisories.
Debian
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Debian 14 | netty-tcnative | No fix yet | — |
| Debian 13 | netty-tcnative | No fix yet | — |
| Debian 12 | netty-tcnative | No fix yet | — |
Ubuntu
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu 26.10 | netty-tcnative | No fix yet | — |
| Ubuntu 26.04 LTS | netty-tcnative | No fix yet | — |
| Ubuntu 24.04 LTS | netty-tcnative | No fix yet | — |
| Ubuntu 22.04 LTS | netty-tcnative | No fix yet | — |
| Ubuntu 20.04 LTS | netty-tcnative | No fix yet | — |
Show 2 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu 18.04 LTS | netty-tcnative | No fix yet | — |
| Ubuntu 16.04 LTS | netty-tcnative | No fix yet | — |
openSUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| openSUSE Tumbleweed | netty-tcnative | 2.0.85-1.1 | openSUSE-SU-2026:12403-1 |
Advisories 1
- openSUSE-SU-2026:12403-1 netty-tcnative-2.0.85-1.1 on GA media SUSE / openSUSE Security Updates · Nov 4, 2026
References
- GitHub Security Advisory (GHSA-2784-hxmm-4hgf) vendor-advisory
- Patch Commit patch
- https://github.com/netty/netty-tcnative/blob/netty-tcnative-parent-2.0.83.Final/openssl-dynamic/src/main/c/sslcontext.c#L2608 technical-description
- netty-tcnative netty-tcnative-parent-2.0.84.Final Release Notes release-notes
- https://github.com/netty/netty-tcnative product
- VulnCheck Advisory: Netty netty-tcnative before 2.0.84.Final SNI Hostname Spoofing via Modified UTF-8 Decoding third-party-advisory