# CVE-2026-50010: Netty disabled TLS hostname verification in netty-handler

Source: https://junglewise.ai/threats/cve-2026-50010-netty-disabled-tls-hostname-verification-in-netty-handler  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-06-12. Updated: 2026-06-15  
License: CC BY 4.0 with a link back

CVE-2026-50010 · Severity: high · CVSS 7.5 · Published 2026-06-12

Netty is a popular networking framework used by many Java applications to handle internet communications. A flaw in how it handles security certificates means that even when developers enable 'hostname verification' (a check to ensure a website is who it says it is), the check may be silently skipped. This could allow an attacker to intercept or eavesdrop on encrypted traffic between a client and a server without being detected.

Technologies: [io.netty:netty-handler (Maven)](https://junglewise.ai/threats/technologies/io-netty-netty-handler). Vendors: [Maven](https://junglewise.ai/threats/vendors/maven).

## Quick answers

**Is CVE-2026-50010 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-50010 being exploited in the wild.

**How severe is CVE-2026-50010?** High severity, with a CVSS score of 7.5, published 12 June 2026.

**Which products and versions are affected?** io.netty:netty-handler (Maven) ECOSYSTEM:introduced=4.2.0.Final,fixed=4.2.15.Final.

**Is there a fix for CVE-2026-50010?** Yes. io.netty:netty-handler (Maven): upgrade to 4.2.15.Final or later. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

**How is CVE-2026-50010 attacked?** It is attacked over the network, in a software library.

**Am I affected by CVE-2026-50010?** Check whether you run io.netty:netty-handler (Maven) 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

- io.netty:netty-handler (Maven): upgrade to 4.2.15.Final or later

  ```sh
  # set io.netty:netty-handler to 4.2.15.Final in your pom.xml or build.gradle
  ```


## Technical details

The vulnerability exists in SimpleTrustManagerFactory.engineGetTrustManagers() and related code paths within the netty-handler package. When a user provides a plain X509TrustManager, Netty wraps it in an X509TrustManagerWrapper. This wrapper extends X509ExtendedTrustManager but incorrectly implements the 3-argument checkServerTrusted method by discarding the SSLEngine parameter and delegating to the 2-argument version. Because the resulting object is technically an instance of X509ExtendedTrustManager, subsequent security layers (like SunJSSE or Netty's OpenSslX509TrustManagerWrapper) fail to apply necessary endpoint identification logic. This results in a complete bypass of hostname verification for clients configured with SslContextBuilder.forClient().trustManager(...). The issue is resolved in versions 4.1.135.Final and 4.2.15.Final.

## Affected products

- Netty netty-handler >= 4.2.0.Final, < 4.2.15.Final
- Netty netty-handler <= 4.1.134.Final

## Identifiers

- CVE-2026-50010
- GHSA-c653-97m9-rcg9

## Timeline

- 2026-06-02: patched: Release of 4.1.135.Final and 4.2.15.Final
- 2026-06-05: disclosed: Initial advisory publication
- 2026-06-12: advisory: NVD publication
- 2026-06-15: advisory: GitHub Advisory reviewed and updated

## References

- [https://github.com/netty/netty/security/advisories/GHSA-c653-97m9-rcg9](https://github.com/netty/netty/security/advisories/GHSA-c653-97m9-rcg9)
- [https://github.com/netty/netty/releases/tag/netty-4.1.135.Final](https://github.com/netty/netty/releases/tag/netty-4.1.135.Final)
- [https://github.com/netty/netty/releases/tag/netty-4.2.15.Final](https://github.com/netty/netty/releases/tag/netty-4.2.15.Final)
- [https://api.github.com/repos/netty/netty/security-advisories/GHSA-c653-97m9-rcg9](https://api.github.com/repos/netty/netty/security-advisories/GHSA-c653-97m9-rcg9)

## Related threats

- [Netty is an asynchronous, event-driven network application framework. Prior to 4.1.137.Final and 4.2.17.Final, the default io.netty.handler.](https://junglewise.ai/threats/cve-2026-75596-netty-quadratic-pre-handshake-clienthello-reassembly-in-sni)
- [Netty SNI routing bypass via fragmented TLS ClientHello](https://junglewise.ai/threats/cve-2026-75595-netty-sni-routing-bypass-via-fragmented-tls-clienthello)
- [Netty excessive memory allocation in SNIHandler](https://junglewise.ai/threats/cve-2026-45416-netty-excessive-memory-allocation-in-snihandler)
- [Netty IPv6 subnet filter bypass in netty-handler](https://junglewise.ai/threats/cve-2026-44249-netty-ipv6-subnet-filter-bypass-in-netty-handler)
- [SslHandler doesn't correctly validate packets which can lead to native crash when using native SSLEngine](https://junglewise.ai/threats/cve-2025-24970-sslhandler-doesn-t-correctly-validate-packets-which-can-lead-to)