PatchSiren cyber security CVE debrief
CVE-2026-50010 netty CVE debrief
CVE-2026-50010 is a HIGH severity vulnerability in Netty, a network application framework. The issue arises from how Netty handles trust managers. Specifically, SimpleTrustManagerFactory.engineGetTrustManagers() and related paths wrap any user-supplied plain X509TrustManager in X509TrustManagerWrapper. This wrapper extends X509ExtendedTrustManager but implements the 3-arg checkServerTrusted(chain, authType, SSLEngine) method by discarding the SSLEngine and calling the 2-arg delegate. As a result, even though Netty 4.2 sets endpointIdentificationAlgorithm=HTTPS by default, a client built with SslContextBuilder.forClient().trustManager(somePlainX509TrustManager) performs no hostname verification at all. This oversight allows for potential man-in-the-middle attacks. The vulnerability has a CVSS score of 7.5 and was published on 2026-06-12T16:16:31.180Z.
- Vendor
- netty
- Product
- Unknown
- CVSS
- HIGH 7.5
- CISA KEV
- Not listed in stored evidence
- Original CVE published
- 2026-06-12
- Original CVE updated
- 2026-06-15
- Advisory published
- 2026-06-12
- Advisory updated
- 2026-06-15
Who should care
Users of Netty, especially those who have built clients using SslContextBuilder.forClient().trustManager(somePlainX509TrustManager), should be aware of this vulnerability. Developers and administrators using Netty versions before 4.1.135.Final and 4.2.15.Final need to update to patched versions to ensure proper hostname verification is performed.
Technical summary
The vulnerability is in the way Netty handles trust managers. Specifically, it incorrectly wraps user-supplied X509TrustManager instances, leading to a lack of hostname verification in clients.
Defensive priority
HIGH
Recommended defensive actions
- Update to Netty version 4.1.135.Final or 4.2.15.Final or later.
- Review and adjust trust manager configurations to ensure proper hostname verification.
Evidence notes
The CVE record [cve-org] and NVD detail [nvd] provide official information about CVE-2026-50010. Additional details can be found in the Netty release notes and security advisories [ref-4], [ref-5], [ref-6].
Official resources
CVE-2026-50010 was published on 2026-06-12T16:16:31.180Z and modified on 2026-06-12T16:18:27.287Z.