CVE-2026-55653

medium

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).

References

https://access.redhat.com/errata/RHSA-2026:89739

https://access.redhat.com/errata/RHSA-2026:82923

https://access.redhat.com/errata/RHSA-2026:82922

https://access.redhat.com/errata/RHSA-2026:82921

https://access.redhat.com/errata/RHSA-2026:82920

https://access.redhat.com/errata/RHSA-2026:82918

https://access.redhat.com/errata/RHSA-2026:82917

https://access.redhat.com/errata/RHSA-2026:82916

https://access.redhat.com/errata/RHSA-2026:82915

https://access.redhat.com/errata/RHSA-2026:82914

https://access.redhat.com/errata/RHSA-2026:82913

https://access.redhat.com/errata/RHSA-2026:82912

https://access.redhat.com/errata/RHSA-2026:82910

https://access.redhat.com/errata/RHSA-2026:82909

https://access.redhat.com/errata/RHSA-2026:82908

https://access.redhat.com/errata/RHSA-2026:82907

https://access.redhat.com/errata/RHSA-2026:82904

https://access.redhat.com/errata/RHSA-2026:82903

https://access.redhat.com/errata/RHSA-2026:82902

https://access.redhat.com/errata/RHSA-2026:82901

https://access.redhat.com/errata/RHSA-2026:82900

https://access.redhat.com/errata/RHSA-2026:82899

https://access.redhat.com/errata/RHSA-2026:82898

https://access.redhat.com/errata/RHSA-2026:82897

https://access.redhat.com/errata/RHSA-2026:82763

https://access.redhat.com/errata/RHSA-2026:82762

https://access.redhat.com/errata/RHSA-2026:82761

https://access.redhat.com/errata/RHSA-2026:82759

https://access.redhat.com/errata/RHSA-2026:82758

https://access.redhat.com/errata/RHSA-2026:82757

https://access.redhat.com/errata/RHSA-2026:82756

https://access.redhat.com/errata/RHSA-2026:82755

https://access.redhat.com/errata/RHSA-2026:82754

https://access.redhat.com/errata/RHSA-2026:82753

https://access.redhat.com/errata/RHSA-2026:82752

https://access.redhat.com/errata/RHSA-2026:82751

https://access.redhat.com/errata/RHSA-2026:82750

https://access.redhat.com/errata/RHSA-2026:82749

https://access.redhat.com/errata/RHSA-2026:80513

https://access.redhat.com/errata/RHSA-2026:76993

https://access.redhat.com/errata/RHSA-2026:76748

https://access.redhat.com/errata/RHSA-2026:58981

https://access.redhat.com/errata/RHSA-2026:54387

https://access.redhat.com/errata/RHSA-2026:47757

https://access.redhat.com/errata/RHSA-2026:47756

https://access.redhat.com/errata/RHSA-2026:47755

https://access.redhat.com/errata/RHSA-2026:36759

Details

Source: Mitre, NVD

Published: 2026-06-23

Updated: 2026-10-26

Risk Information

CVSS v2

Base Score: 7.8

Vector: CVSS2#AV:N/AC:L/Au:N/C:N/I:N/A:C

Severity: High

CVSS v3

Base Score: 6.5

Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H

Severity: Medium

EPSS

EPSS: 0.0053