CVE-2026-100665
Description
A flaw was found in Netty. During certificate validation for Quick UDP Internet Connections (QUIC), standard trust managers fail to perform endpoint identification to confirm the server's identity. A remote attacker positioned on the network path can exploit this flaw by presenting a valid certificate for an unrelated domain during connection establishment. This allows the attacker to bypass hostname verification, impersonate trusted servers, and intercept sensitive communications.
Statement
This vulnerability is rated as having an Important impact because a man-in-the-middle attacker on the network path can impersonate remote servers and intercept sensitive communication without triggering certificate validation errors. The issue specifically affects outbound client connections leveraging Netty's QUIC codec when standard trust managers are used without extended endpoint identification. Server deployments and client applications utilizing standard TLS transports or extended trust managers are not impacted.
Mitigation
Mitigation for this issue is either not available or the currently available options do not meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base, or stability.
Common Vulnerability Scoring System (CVSS) Score Details
Info alert:Important note
CVSS scores for open source components depend on vendor-specific factors (e.g. version or build chain). Therefore, Red Hat's score and impact rating can be different from NVD and other vendors. Red Hat remains the authoritative CVE Naming Authority (CNA) source for its products and services (see Red Hat classifications).
The following CVSS metrics and score provided are preliminary and subject to review.
CVSS v3 Score Breakdown
| Red Hat | NVD | cve.org | |
|---|---|---|---|
| Base Score | 7.5 | N/A | 7.5 |
| Attack Vector | Network | N/A | Network |
| Attack Complexity | Low | N/A | Low |
| Privileges Required | None | N/A | None |
| User Interaction | None | N/A | None |
| Scope | Unchanged | N/A | Unchanged |
| Confidentiality | High | N/A | High |
| Integrity Impact | None | N/A | None |
| Availability Impact | None | N/A | None |
Vector
Red Hat: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
cve.org: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
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