CVE-2026-55653
4.3 · MEDIUMOverview
CVE-2026-55653 is a medium-severity vulnerability affecting openbsd openssh. It was published on June 23, 2026 and has a CVSS 3.1 base score of 4.3 (MEDIUM).
This vulnerability has a CVSS 3.1 base score of 4.3, rated MEDIUM. It can be exploited remotely over the network. No authentication or special privileges are required for exploitation.
Technical 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).
Remediation
Check the references section for vendor advisories and patches from openbsd. Update openssh to the latest patched version. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.
Affected Products
| Vendor | Product | Versions | Status |
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References
Frequently Asked Questions
What is CVE-2026-55653?
CVE-2026-55653 is a medium-severity vulnerability affecting openbsd openssh. It was published on June 23, 2026 and has a CVSS 3.1 base score of 4.3 (MEDIUM).
How severe is CVE-2026-55653?
This vulnerability has a CVSS 3.1 base score of 4.3, rated MEDIUM. It can be exploited remotely over the network. No authentication or special privileges are required for exploitation.
How do I fix or remediate CVE-2026-55653?
Check the references section for vendor advisories and patches from openbsd. Update openssh to the latest patched version. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.
How can CyberStrike help with CVE-2026-55653?
CyberStrike's AI-powered security agents can automatically detect CVE-2026-55653 across your infrastructure using autonomous pentesting, DAST scanning, and HackBrowser. The platform continuously monitors for known vulnerabilities and provides actionable remediation guidance prioritized by real-world exploitability.
How CyberStrike Helps
AI agents map your attack surface to find vulnerabilities like this one.
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