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CVE-2026-65637

tomcat: Apache Tomcat: Improper Input Validation allows HTTP/2 no-authority bypass of strict SNI validation

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Severity

Moderate

Red Hat Product Security

6.5

CVSS 3.1

Review impact separately from score.

Published · August 26, 2026

Updated · November 2, 2026

Description

A flaw was found in Apache Tomcat. This improper input validation vulnerability, stemming from an incomplete fix for CVE-2026-32990, allows for an HTTP/2 no-authority bypass of strict Server Name Indication (SNI) validation. This could potentially lead to unauthorized access or misrouting of requests.

Statement

This Moderate flaw in Apache Tomcat allows an HTTP/2 no-authority bypass of strict Server Name Indication (SNI) validation due to improper input handling. This could lead to requests being misrouted to an unintended virtual host, potentially exposing sensitive information or causing service disruption in specific configurations. The impact is limited as it primarily affects request routing rather than arbitrary code execution.

CVSS score applicability

The CVSS score(s) listed for this vulnerability do not reflect the associated product's status, and are included for informational purposes to better understand the severity of this vulnerability.

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.

CVSS / CWE

CVSS 3.1 · 6.5
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N

CWE-444 · Inconsistent Interpretation of HTTP Requests