Description
Netty netty-tcnative before 2.0.84.Final contains a denial of service vulnerability in the tcn_write_to_bytebuffer BIO write callback that overreports bytes consumed. Remote TLS 1.3 peers can provoke queued post-handshake records like NewSessionTicket or KeyUpdate to truncate flights, fail connections, or abort the JVM process.
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-9xr3-jwv4-r489) vendor-advisory
- Patch Commit patch
- https://github.com/netty/netty-tcnative/blob/netty-tcnative-parent-2.0.83.Final/openssl-dynamic/src/main/c/ssl.c#L240 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-tcnative before 2.0.84.Final Denial of Service via BIO Write Overcount third-party-advisory