Bug 2526734

Summary: CVE-2026-62243 python-avro: Netty: TLS hostname verification bypass via OpenSSL client path misconfiguration [fedora-all]
Product: [Fedora] Fedora Reporter: Matteo Signorini <msignori>
Component: python-avroAssignee: dev
Status: NEW --- QA Contact:
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Priority: high    
Version: rawhideCC: dev
Target Milestone: ---Keywords: Security, SecurityTracking
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Hardware: Unspecified   
OS: Unspecified   
Whiteboard: {"flaws": ["2ab98834-161b-4fba-9b79-a53396b6593f"]}
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oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
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Bug Depends On:    
Bug Blocks: 2521309    

Description Matteo Signorini 2026-09-01 10:52:09 UTC 
Disclaimer: Community trackers are created by Red Hat Product Security team on a best effort basis. Package maintainers are required to ascertain if the flaw indeed affects their package, before starting the update process.

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.