CVE-2026-55653: Double Free in Red Hat Red Hat Enterprise Linux 10
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).
AI Analysis
Technical Summary
CVE-2026-55653 is a double free vulnerability in the OpenSSH client path for Diffie-Hellman Group Exchange (DH-GEX) when operating in FIPS mode known-group validation. A malicious SSH server can send attacker-controlled DH-GEX group parameters that trigger a double free condition, causing the client process to crash and leading to denial of service. This issue affects Red Hat Hardened Images and Red Hat Enterprise Linux 8 OpenSSH packages. Red Hat has issued security advisories and updates (e.g., openssh-10.3p1-6.hum1 for Hardened Images and openssh-8.0p1-30.el8_10 for RHEL 8) to remediate the vulnerability.
Potential Impact
Successful exploitation causes client-side process termination resulting in denial of service (DoS). There is no indication of confidentiality or integrity impact. The vulnerability requires user interaction (UI:R) and network attack vector (AV:N). No known exploits in the wild have been reported.
Mitigation Recommendations
Red Hat has released security updates for OpenSSH packages that address this vulnerability. Users should apply the updates provided in the advisories RHSA-2026:36759 for Red Hat Hardened Images and RHSA-2026:47755 for Red Hat Enterprise Linux 8. Details and update instructions are available at https://access.redhat.com/security/cve/CVE-2026-55653 and https://access.redhat.com/articles/11258. Patch status for Red Hat Enterprise Linux 10 is not explicitly confirmed; check the vendor advisory for current remediation guidance.
CVE-2026-55653: Double Free in Red Hat Red Hat Enterprise Linux 10
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).
CVSS v3.1
Score 4.3medium
AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
CVE-2026-55653 is a double free vulnerability in the OpenSSH client path for Diffie-Hellman Group Exchange (DH-GEX) when operating in FIPS mode known-group validation. A malicious SSH server can send attacker-controlled DH-GEX group parameters that trigger a double free condition, causing the client process to crash and leading to denial of service. This issue affects Red Hat Hardened Images and Red Hat Enterprise Linux 8 OpenSSH packages. Red Hat has issued security advisories and updates (e.g., openssh-10.3p1-6.hum1 for Hardened Images and openssh-8.0p1-30.el8_10 for RHEL 8) to remediate the vulnerability.
Potential Impact
Successful exploitation causes client-side process termination resulting in denial of service (DoS). There is no indication of confidentiality or integrity impact. The vulnerability requires user interaction (UI:R) and network attack vector (AV:N). No known exploits in the wild have been reported.
Mitigation Recommendations
Red Hat has released security updates for OpenSSH packages that address this vulnerability. Users should apply the updates provided in the advisories RHSA-2026:36759 for Red Hat Hardened Images and RHSA-2026:47755 for Red Hat Enterprise Linux 8. Details and update instructions are available at https://access.redhat.com/security/cve/CVE-2026-55653 and https://access.redhat.com/articles/11258. Patch status for Red Hat Enterprise Linux 10 is not explicitly confirmed; check the vendor advisory for current remediation guidance.
Technical Details
- Data Version
- 5.2
- Assigner Short Name
- redhat
- Date Reserved
- 2026-06-16T23:55:05.737Z
- Cvss Version
- 3.1
- State
- PUBLISHED
- Remediation Level
- null
- Vendor Advisory Urls
- [{"url":"https://access.redhat.com/security/cve/CVE-2026-55653","vendor":"Red Hat"}]
Threat ID: 6a3a0366eed863c81e190b81
Added to database: 06/23/2026, 03:54:14 UTC
Last enriched: 07/30/2026, 21:43:07 UTC
Last updated: 08/07/2026, 00:41:15 UTC
Views: 90
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