Is CVE-2026-116541 exploited in the wild?

No. Junglewise Threat Intelligence has no report of CVE-2026-116541 being exploited in the wild.

How severe is CVE-2026-116541?

Medium severity, with a CVSS score of 5.9, published 26 October 2026.

Which products and versions are affected?

Netty-Tcnative before 2.0.84.Final; Netty-Tcnative-Boringssl-Static before 2.0.84.Final.

Is there a fix for CVE-2026-116541?

Yes: fixed in 2.0.84.Final. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

How is CVE-2026-116541 attacked?

It is attacked over the network, in a software library.

Am I affected by CVE-2026-116541?

Check whether you run Netty-Tcnative or Netty-Tcnative-Boringssl-Static at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

CVE-2026-116541: Netty netty-tcnative denial of service in BIO write callback

CVE-2026-116541 · Severity: medium · CVSS 5.9 · Published 2026-10-26

Netty's TLS library contains a flaw in how it reports bytes consumed by the BIO write callback, allowing remote TLS 1.3 peers to send specially crafted post-handshake records. This can cause connections to fail, truncate message flights, or crash the Java process hosting the application, leading to service disruption.

Technologies: Netty-Tcnative. Vendors: Netty.

Quick answers

Is CVE-2026-116541 exploited in the wild?: No. Junglewise Threat Intelligence has no report of CVE-2026-116541 being exploited in the wild.
How severe is CVE-2026-116541?: Medium severity, with a CVSS score of 5.9, published 26 October 2026.
Which products and versions are affected?: Netty-Tcnative before 2.0.84.Final; Netty-Tcnative-Boringssl-Static before 2.0.84.Final.
Is there a fix for CVE-2026-116541?: Yes: fixed in 2.0.84.Final. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.
How is CVE-2026-116541 attacked?: It is attacked over the network, in a software library.
Am I affected by CVE-2026-116541?: Check whether you run Netty-Tcnative or Netty-Tcnative-Boringssl-Static at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

How to fix

Fixed in: 2.0.84.Final

Technical details

The tcn_write_to_bytebuffer BIO write callback in netty-tcnative incorrectly overreports the number of bytes consumed, causing buffer management errors when handling TLS 1.3 post-handshake messages (NewSessionTicket, KeyUpdate). A remote peer can exploit this over the network to trigger denial of service without authentication by sending malformed or oversized post-handshake records.

Affected products

Netty netty-tcnative before 2.0.84.Final
Netty netty-tcnative-boringssl-static before 2.0.84.Final

Timeline

2026-10-26: disclosed

References

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