CVE-2026-100665 Netty - Authentication Bypass

Netty 4.2.11.Final < 4.2.18.Final contains a broken authentication caused by incomplete hostname verification in QUIC certificate verification with plain X509TrustManager, letting network attackers bypass hostname authentication, exploit requires network access.

CVSS base score 7.5 /10
High
CISA KEV
Not listed
Public exploit
None known
Authentication
Not required
EPSS
0.29% chance of exploitation in 30 days
View the NVD record ↗

Details

Type
Authentication Bypass
Impact
Man In The Middle
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
Published
26 September 2026
Updated
15 October 2026
Weakness
CWE-295

Vendor fix

Upgrade to version 4.2.18.Final or later.

Patching closes this CVE. It does not tell you which of your systems run the affected version, or what else is exposed alongside them.

References

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