CVE-2026-55653

Published Jun 23, 2026

Last updated a day ago

CVSS medium 4.3

Overview

Description
A flaw was found in OpenSSH. A malicious SSH server can exploit a double free vulnerability in the Diffie-Hellman Group Exchange (DH-GEX) client path. This occurs during FIPS (Federal Information Processing Standards) mode known-group validation when the client processes attacker-controlled DH-GEX group parameters. Successful exploitation leads to client-side process termination, resulting in a Denial of Service (DoS).
Source
secalert@redhat.com
NVD status
Analyzed
Products
openssh, hardened_images, openshift_container_platform, enterprise_linux

Risk scores

CVSS 3.1

Type
Primary
Base score
6.5
Impact score
3.6
Exploitability score
2.8
Vector string
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H
Severity
MEDIUM

Weaknesses

secalert@redhat.com
CWE-415

Social media

Hype score
Not currently trending

  1. 🚨*CVE* CVE-2026-55653 A flaw was found in OpenSSH. A malicious SSH server can exploit a double free vulnerability in the Diffie-Hellman Group Exchange (DH-GEX) client path. This occurs dur… https://t.co/OQsczn2ibx ----- Traducción: Se encontró una fa… https://t.co/utmtN

    @infoflowcloud

    23 Jun 2026

    32 Impressions

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Configurations

Related CVEs

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References

Sources include official advisories and independent security research.