# CVE-2026-62243: Netty 4.2.0 through 4.2.16 TLS Hostname Verification Bypass

> CVE-2026-62243: Netty 4.2.0 through 4.2.16 TLS Hostname Verification Bypass. CVSS 7.5 (CVSS 3.1).

Canonical: https://rewindex.com/cve/CVE-2026-62243
Last updated: 2026-10-14T19:10:00Z

- Published: 2026-08-22 12:26 UTC · Updated: 2026-10-14 19:10 UTC · Assigner: VulnCheck
- CVSS: 7.5 (CVSS 3.1) · Severity: High · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
- EPSS: 0.16%, 5th percentile (scored 2026-10-25)
- CISA KEV: no
- CWE: CWE-297

## 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.

## Affected vendors and products

- netty: netty

## Tracked companies

- [Confluence](https://rewindex.com/company/confluence.md)
- [Jira](https://rewindex.com/company/jira.md)

## References

- [CVE record on cve.org](https://www.cve.org/CVERecord?id=CVE-2026-62243)
- [NVD entry](https://nvd.nist.gov/vuln/detail/CVE-2026-62243)
- [https://github.com/netty/netty/security/advisories/GHSA-p85m-gvr3-788c](https://github.com/netty/netty/security/advisories/GHSA-p85m-gvr3-788c)
- [https://www.vulncheck.com/advisories/netty-through-tls-hostname-verification-bypass](https://www.vulncheck.com/advisories/netty-through-tls-hostname-verification-bypass)

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_Sources: CVE records from the CVE Program (cve.org). CVE® is a registered trademark of The MITRE Corporation. (https://www.cve.org/) This product uses data from the NVD API but is not endorsed or certified by the NVD. (https://nvd.nist.gov/) Known Exploited Vulnerabilities catalog from CISA. (https://www.cisa.gov/known-exploited-vulnerabilities-catalog) EPSS scores from FIRST (Exploit Prediction Scoring System). (https://www.first.org/epss/)_


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Canonical: https://rewindex.com/cve/CVE-2026-62243 · Markdown: https://rewindex.com/cve/CVE-2026-62243.md · JSON: https://rewindex.com/api/v1/cves/CVE-2026-62243 · Data licensed CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/) · Generated 2026-10-26T02:06:21.993Z