Vulnerabilities
Misconfiguration
Compliance
Cryptography
CVE Vulnerabilities

CVE-2026-55653

Double Free

Published: Jun 23, 2026 | Modified: Oct 30, 2026
CVSS 3.x
6.5
MEDIUM
Source:
NVD
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H
CVSS 2.x
RedHat/V2
RedHat/V3
4.3 MODERATE
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:L
Ubuntu
MEDIUM
Vulnerability-free packages from our partners
Additional information
NVDhttps://nvd.nist.gov/vuln/detail/CVE-2026-55653
CWEhttps://cwe.mitre.org/data/definitions/415.html

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).

Weakness

The product calls free() twice on the same memory address.

Affected Software

NameVendorStart VersionEnd Version
OpensshOpenbsd- (including)- (including)
Hardened_imagesRedhat- (including)- (including)
Openshift_container_platformRedhat4.0 (including)4.0 (including)
Enterprise_linuxRedhat6.0 (including)6.0 (including)
Enterprise_linuxRedhat7.0 (including)7.0 (including)
Enterprise_linuxRedhat8.0 (including)8.0 (including)
Enterprise_linuxRedhat9.0 (including)9.0 (including)
Enterprise_linuxRedhat10.0 (including)10.0 (including)
Red Hat Enterprise Linux 10RedHatopenssh-0:9.9p1-25.el10_2*
Red Hat Enterprise Linux 10.0 Extended Update SupportRedHatopenssh-0:9.9p1-7.el10_0.5*
Red Hat Enterprise Linux 8RedHatopenssh-0:8.0p1-30.el8_10*
Red Hat Enterprise Linux 8RedHatopenssh-0:8.0p1-30.el8_10*
Red Hat Enterprise Linux 9RedHatopenssh-0:9.9p1-9.el9_8*
Red Hat Enterprise Linux 9RedHatopenssh-0:9.9p1-9.el9_8*
Red Hat Enterprise Linux 9.2 Update Services for SAP SolutionsRedHatopenssh-0:8.7p1-30.el9_2.13*
Red Hat Enterprise Linux 9.4 Update Services for SAP SolutionsRedHatopenssh-0:8.7p1-38.el9_4.10*
Red Hat Enterprise Linux 9.6 Extended Update SupportRedHatopenssh-0:8.7p1-45.el9_6.5*
Red Hat Hardened ImagesRedHatopenssh-main-10.3p1-6.hum1*
Red Hat OpenShift AI 3.0RedHatrhai/base-image-cuda-rhel9:1791818590*
Red Hat OpenShift AI 3.0RedHatrhai/base-image-cpu-rhel9:1791818589*
Red Hat OpenShift AI 3.0RedHatrhai/base-image-spyre-rhel9:1791818505*
Red Hat OpenShift AI 3.0RedHatrhai/base-image-tpu-rhel9:1791818496*
Red Hat OpenShift AI 3.0RedHatrhai/base-image-rocm-rhel9:1791818502*
Red Hat OpenShift AI 3.0RedHatrhai/base-image-cpu-rhel9:1793042072*
Red Hat OpenShift AI 3.2RedHatrhai/base-image-spyre-rhel9:1791818602*
Red Hat OpenShift AI 3.2RedHatrhai/base-image-cpu-rhel9:1791818598*
Red Hat OpenShift AI 3.2RedHatrhai/base-image-tpu-rhel9:1791818512*
Red Hat OpenShift AI 3.2RedHatrhai/base-image-cuda-rhel9:1791818587*
Red Hat OpenShift AI 3.2RedHatrhai/base-image-rocm-rhel9:1791818778*
Red Hat OpenShift AI 3.2RedHatrhai/base-image-rocm-rhel9:1791818512*
Red Hat OpenShift AI 3.3RedHatrhai/base-image-tpu-rhel9:1791818782*
Red Hat OpenShift AI 3.3RedHatrhai/base-image-rocm-6.4-rhel9:1791818782*
Red Hat OpenShift AI 3.3RedHatrhai/base-image-cuda-12.9-rhel9:1791818627*
Red Hat OpenShift AI 3.3RedHatrhai/base-image-rocm-7.0-rhel9:1791818790*
Red Hat OpenShift AI 3.3RedHatrhai/base-image-cpu-rhel9:1791818874*
Red Hat OpenShift AI 3.3RedHatrhai/base-image-neuron-rhel9:1791818792*
Red Hat OpenShift AI 3.3RedHatrhai/base-image-cuda-13.0-rhel9:1791818662*
Red Hat OpenShift AI 3.3RedHatrhai/base-image-spyre-rhel9:1791818877*
Red Hat OpenShift AI 3.4RedHatrhai/base-image-neuron-rhel9:1791883722*
Red Hat OpenShift AI 3.4RedHatrhai/base-image-cuda-12.9-rhel9:1791881612*
Red Hat OpenShift AI 3.4RedHatrhai/base-image-cpu-rhel9:1791885618*
Red Hat OpenShift AI 3.4RedHatrhai/base-image-rocm-6.4-rhel9:1791881487*
Red Hat OpenShift AI 3.4RedHatrhai/base-image-spyre-rhel9:1791881732*
Red Hat OpenShift AI 3.4RedHatrhai/base-image-rocm-7.1-rhel9:1791883315*
Red Hat OpenShift AI 3.4RedHatrhai/base-image-gaudi-rhel9:1791881486*
Red Hat OpenShift AI 3.4RedHatrhai/base-image-tpu-rhel9:1791881769*
Red Hat OpenShift AI 3.4RedHatrhai/base-image-cuda-13.0-rhel9:1791885505*
Red Hat OpenShift AI 3.5RedHatrhai/base-image-spyre-rhel9:1791819252*
Red Hat OpenShift AI 3.5RedHatrhai/base-image-gaudi-rhel9:1791818749*
Red Hat OpenShift AI 3.5RedHatrhai/base-image-cpu-rhel9:1791819206*
Red Hat OpenShift AI 3.5RedHatrhai/base-image-neuron-rhel9:1791818979*
Red Hat OpenShift AI 3.5RedHatrhai/base-image-rocm-7.14-rhel9:1791819123*
Red Hat OpenShift AI 3.5RedHatrhai/base-image-tpu-rhel9:1791818901*
Red Hat OpenShift AI 3.5RedHatrhai/base-image-rubin-rhel9:1791820333*
Red Hat OpenShift AI 3.5RedHatrhai/base-image-cuda-13.0-rhel9:1791819495*
Red Hat OpenShift AI 3.5RedHatrhai/base-image-cuda-12.9-rhel9:1791819104*
Red Hat Update Infrastructure 5RedHatrhui5/installer-rhel9:1786435483*
Red Hat Update Infrastructure 5RedHatrhui5/rhua-rhel9:1786533529*
Red Hat Update Infrastructure 5RedHatrhui5/installer-tp-rhel9:1787135742*
Red Hat Update Infrastructure 5RedHatrhui5/rhua-tp-rhel9:1787241260*
Openssh-ssh1Ubuntudevel*
Openssh-ssh1Ubuntuesm-apps/bionic*
Openssh-ssh1Ubuntuesm-apps/focal*
Openssh-ssh1Ubuntuesm-apps/jammy*
Openssh-ssh1Ubuntuesm-apps/noble*
Openssh-ssh1Ubuntuesm-apps/resolute*
Openssh-ssh1Ubuntujammy*
Openssh-ssh1Ubuntunoble*
Openssh-ssh1Ubuntuquesting*
Openssh-ssh1Ubunturesolute*
Openssh-ssh1Ubuntustonking*
Openssh-ssh1Ubuntuupstream*

Potential Mitigations

References

Aqua Security is the largest pure-play cloud native security company, providing customers the freedom to innovate and run their businesses with minimal friction. The Aqua Cloud Native Security Platform provides prevention, detection, and response automation across the entire application lifecycle to secure the build, secure cloud infrastructure and secure running workloads wherever they are deployed.
Copyright © 2026 Aqua Security Software Ltd.   Privacy Policy | Terms of Use