Vulnerability Monitor

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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 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).


Security Impact Summary

This vulnerability carries a MEDIUM severity rating with a CVSS v3.1 score of 4.3, indicating it can be exploited remotely over the network with relatively low complexity though user interaction is required and does not require pre-existing privileges . The vulnerability impacts and limited availability for affected systems. Impacting 4 products from openbsd, from redhat, from redhat and 1 other, organizations running these solutions should prioritize assessment and patching.

Historical Context

Reported in 2026, this vulnerability emerged during an era marked by increased sophistication in supply chain attacks, cloud infrastructure vulnerabilities, and software-as-a-service (SaaS) security challenges. Security practices during this period emphasized zero-trust architectures, container security, and API protection.


Published

2026-06-23T04:17:36.600

Last Modified

2026-07-30T09:16:35.310

Status

Modified

Source

[email protected]

Severity

CVSSv3.1: 4.3 (MEDIUM)

Weaknesses
  • Type: Secondary
    CWE-415

Affected Vendors & Products
Type Vendor Product Version/Range Vulnerable?
Application openbsd openssh - Yes
Application redhat hardened_images - Yes
Application redhat openshift_container_platform 4.0 Yes
Operating System redhat enterprise_linux 6.0 Yes
Operating System redhat enterprise_linux 7.0 Yes
Operating System redhat enterprise_linux 8.0 Yes
Operating System redhat enterprise_linux 9.0 Yes
Operating System redhat enterprise_linux 10.0 Yes

References

How SecUtils Interprets This CVE

SecUtils normalizes and enriches National Vulnerability Database (NVD) records by standardizing vendor and product identifiers, aggregating vulnerability metadata from both NVD and MITRE sources, and providing structured context for security teams. For openbsd's affected products, we extract Common Platform Enumeration (CPE) data, Common Weakness Enumeration (CWE) classifications, CVSS severity metrics, and reference data to enable rapid vulnerability prioritization and asset correlation. This record contains no exploit code, proof-of-concept instructions, or attack methodologies—only defensive intelligence necessary for patch management, risk assessment, and security operations.