CVE-2026-75595

Netty is an asynchronous, event-driven network application framework. Prior to 4.1.137.Fina and 4.2.17.Final, io.netty.handler.ssl.SslClientHelloHandler#decode checks the wrong offset before reading the four-byte TLS handshake header, so a ClientHello whose handshake header spans records can cause an IndexOutOfBoundsException and invoke select(ctx, null). This selects the default SslContext instead of the SNI-specific context. In deployments where per-SNI clientAuth=REQUIRE is the sole mutual TLS gate, the default SslContext uses clientAuth=NONE or clientAuth=OPTIONAL, and no application-layer certificate verification exists, an unauthenticated remote attacker can bypass the protected route's mutual TLS requirement. This issue is fixed in versions 4.1.137.Final and 4.2.17.Final.

CVSS

No CVSS.

References

Link	Resource
https://github.com/netty/netty/commit/1b5abc6443b63726c72cdd285af2feb7ddbb8ff7
https://github.com/netty/netty/commit/9e0519239108a69b7e9bbc5e9182ee139a0d7961
https://github.com/netty/netty/pull/17213
https://github.com/netty/netty/pull/17217
https://github.com/netty/netty/releases/tag/netty-4.1.137.Final
https://github.com/netty/netty/releases/tag/netty-4.2.17.Final
https://github.com/netty/netty/security/advisories/GHSA-c4c3-7fpv-j4q5

Configurations

No configuration.

History

No history.

Information

Published : 2026-08-19 21:17

Updated : 2026-09-09 21:19

NVD link : CVE-2026-75595

Mitre link : CVE-2026-75595

CVE.ORG link : CVE-2026-75595

JSON object : View

Products Affected

No product.

CWE

CWE-754

Improper Check for Unusual or Exceptional Conditions

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