CVE-2026-62243
Netty 4.2.0 through 4.2.16 TLS Hostname Verification Bypass
- State
- Published
- Severity
- 8.7 High
- Published
- Aug 22, 2026
- Updated
- Aug 24, 2026
- Reserved
- Jul 13, 2026
Description
Netty (io.netty:netty-handler) versions from 4.2.0.Final through 4.2.16.Final and versions through 4.1.136.Final disable TLS hostname verification on the SslProvider.OPENSSL client path when a plain (non-extended) X509TrustManager is used and Unsafe-based trust-manager wrapping is unavailable (Java 25+). In this configuration the OpenSSL client does not perform hostname verification, allowing a man-in-the-middle attacker to present a certificate issued for a different hostname that is accepted without validation. Fixed in 4.2.17.Final and 4.1.137.Final.
Scores
| CVSS | Score | Vector | Source |
|---|---|---|---|
| 4.0 | 8.7 High | CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N | VulnCheck |
| 3.1 | 7.5 High | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N | VulnCheck |
Weaknesses
- CWE-297 Improper Validation of Certificate with Host Mismatch
Affected Products
| Product | Versions |
|---|---|
nettynetty |
|
nettynetty |
|
References
- GitHub Security Advisory (GHSA-p85m-gvr3-788c)vendor-advisory
- VulnCheck Advisory: Netty 4.2.0 through 4.2.16 TLS Hostname Verification Bypassthird-party-advisory
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