CVE-2026-97031
Description
A flaw was found in crypto/tls. A remote attacker can trigger this vulnerability by sending a specially crafted packet containing multiple Encrypted Client Hello (ECH) outer extension references to a server. Processing these unauthorized references leads to excessive memory consumption, causing a Denial of Service (DoS) through server crashes or unresponsiveness.
Statement
This vulnerability is rated as an Important severity flaw because an unauthenticated remote attacker can trigger memory exhaustion and crash server processes without requiring privileges or user interaction. Go applications that terminate TLS connections and accept Encrypted Client Hello configurations are vulnerable to resource amplification during the initial handshake. While the flaw does not facilitate arbitrary code execution or compromise data confidentiality, the resulting denial of service can disrupt critical network services.
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).
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 | None | N/A | None |
| Integrity Impact | None | N/A | None |
| Availability Impact | High | N/A | High |
Vector
Red Hat: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
cve.org: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
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