CVE-2026-55653
Openssh: double free in red hat enterprise linux versions of openssh dh-gex client path during fips known-group validation leads to client-side denial of service
CVE-2026-55653 is fixed in 17 products on 1 platform, first by ALSA-2026:47757, released July 29, 2026. It is not reported as exploited. Patch Radar priority: High.
High
CVSS
7.7
Moderate
Exploitation
None reported
No vendor assessment
CISA KEV
Not listed
Not in the Known Exploited Vulnerabilities catalog
EPSS
0.0053
45th percentile
OpenSSH is an SSH protocol implementation supported by a number of Linux, UNIX, and similar operating systems. It includes the core files necessary for both the OpenSSH client and server. Security Fix(es): * openssh: Local MITM of X11 forwarding via abstract UNIX socket pre-binding in Red Hat Enterprise Linux OpenSSH client versions (CVE-2026-55655) * openssh: Double free in Red Hat Enterprise Linux versions of OpenSSH DH-GEX client path during FIPS known-group validation leads to client-side denial of service (CVE-2026-55653) For more details about the security issue(s), including the impact, a CVSS score, acknowledgments, and other related information, refer to the CVE page(s) listed in the References section.
Where it's fixed
| Product | Fixed in | Fix | Released |
|---|---|---|---|
| Linux | |||
| openssh · RHEL 10 | 9.9p1-7.el10_0.5 | RHSA-2026:76748 | Jul 31, 2026 |
| openssh · RHEL 8 | 0:8.0p1-30.el8_10 | RHSA-2026:47755 | Jul 31, 2026 |
| openssh · RHEL 9 | 0:9.9p1-9.el9_8 | RHSA-2026:47756 | Jul 31, 2026 |
| openssh · almalinux 10 | 9.9p1-25.el10_2.alma.1 | ALSA-2026:47757 | Jul 29, 2026 |
| openssh · almalinux 8 | 8.0p1-30.el8_10 | ALSA-2026:47755 | Jul 29, 2026 |
| openssh · almalinux 9 | 9.9p1-9.el9_8.alma.1 | ALSA-2026:47756 | Jul 29, 2026 |
| openssh · amzn 2023 | 9.9p1-10.amzn2023.0.1 | ALAS2023-2026-2031 | Aug 3, 2026 |
| openssh · ol 10 | 0:9.9p1-25.0.1.el10_2 | ELSA-2026-47757 | Jul 30, 2026 |
| openssh · ol 8 | 0:8.0p1-30.0.1.el8_10 | ELSA-2026-47755 | Jul 31, 2026 |
| openssh · ol 9 | 0:9.9p1-9.0.1.el9_8 | ELSA-2026-47756 | Aug 6, 2026 |
| openssh · rocky 10 | 0:9.9p1-25.el10_2.rocky.0.1 | RLSA-2026:47757 | Jul 30, 2026 |
| openssh · rocky 8 | 0:8.0p1-30.el8_10 | RLSA-2026:47755 | Jul 30, 2026 |
| openssh · rocky 9 | 0:9.9p1-9.el9_8.rocky.0.1 | RLSA-2026:47756 | Jul 30, 2026 |
| openssh-askpass · RHEL 8 | 0:8.0p1-30.el8_10 | RHSA-2026:47755 | Jul 31, 2026 |
| openssh-askpass · RHEL 9 | 0:9.9p1-9.el9_8 | RHSA-2026:47756 | Jul 31, 2026 |
| openssh-askpass · almalinux 10 | 9.9p1-25.el10_2.alma.1 | ALSA-2026:47757 | Jul 29, 2026 |
| openssh-askpass · almalinux 8 | 8.0p1-30.el8_10 | ALSA-2026:47755 | Jul 29, 2026 |
| openssh-askpass · almalinux 9 | 9.9p1-9.el9_8.alma.1 | ALSA-2026:47756 | Jul 29, 2026 |
| openssh-askpass · ol 10 | 0:9.9p1-25.0.1.el10_2 | ELSA-2026-47757 | Jul 30, 2026 |
| openssh-askpass · ol 8 | 0:8.0p1-30.0.1.el8_10 | ELSA-2026-47755 | Jul 31, 2026 |
| openssh-askpass · ol 9 | 0:9.9p1-9.0.1.el9_8 | ELSA-2026-47756 | Aug 6, 2026 |
| openssh-cavs · RHEL 8 | 0:8.0p1-30.el8_10 | RHSA-2026:47755 | Jul 31, 2026 |
| openssh-cavs · almalinux 8 | 8.0p1-30.el8_10 | ALSA-2026:47755 | Jul 29, 2026 |
| openssh-cavs · ol 8 | 0:8.0p1-30.0.1.el8_10 | ELSA-2026-47755 | Jul 31, 2026 |
| openssh-clients · RHEL 8 | 0:8.0p1-30.el8_10 | RHSA-2026:47755 | Jul 31, 2026 |
| openssh-clients · RHEL 9 | 0:9.9p1-9.el9_8 | RHSA-2026:47756 | Jul 31, 2026 |
| openssh-clients · almalinux 10 | 9.9p1-25.el10_2.alma.1 | ALSA-2026:47757 | Jul 29, 2026 |
| openssh-clients · almalinux 8 | 8.0p1-30.el8_10 | ALSA-2026:47755 | Jul 29, 2026 |
| openssh-clients · almalinux 9 | 9.9p1-9.el9_8.alma.1 | ALSA-2026:47756 | Jul 29, 2026 |
| openssh-clients · amzn 2023 | 9.9p1-10.amzn2023.0.1 | ALAS2023-2026-2031 | Aug 3, 2026 |
| openssh-clients · ol 10 | 0:9.9p1-25.0.1.el10_2 | ELSA-2026-47757 | Jul 30, 2026 |
| openssh-clients · ol 8 | 0:8.0p1-30.0.1.el8_10 | ELSA-2026-47755 | Jul 31, 2026 |
| openssh-clients · ol 9 | 0:9.9p1-9.0.1.el9_8 | ELSA-2026-47756 | Aug 6, 2026 |
| openssh-clients-debuginfo · amzn 2023 | 9.9p1-10.amzn2023.0.1 | ALAS2023-2026-2031 | Aug 3, 2026 |
| openssh-debuginfo · amzn 2023 | 9.9p1-10.amzn2023.0.1 | ALAS2023-2026-2031 | Aug 3, 2026 |
| openssh-debugsource · amzn 2023 | 9.9p1-10.amzn2023.0.1 | ALAS2023-2026-2031 | Aug 3, 2026 |
| openssh-keycat · RHEL 8 | 0:8.0p1-30.el8_10 | RHSA-2026:47755 | Jul 31, 2026 |
| openssh-keycat · RHEL 9 | 0:9.9p1-9.el9_8 | RHSA-2026:47756 | Jul 31, 2026 |
| openssh-keycat · almalinux 10 | 9.9p1-25.el10_2.alma.1 | ALSA-2026:47757 | Jul 29, 2026 |
| openssh-keycat · almalinux 8 | 8.0p1-30.el8_10 | ALSA-2026:47755 | Jul 29, 2026 |
| openssh-keycat · almalinux 9 | 9.9p1-9.el9_8.alma.1 | ALSA-2026:47756 | Jul 29, 2026 |
| openssh-keycat · amzn 2023 | 9.9p1-10.amzn2023.0.1 | ALAS2023-2026-2031 | Aug 3, 2026 |
| openssh-keycat · ol 10 | 0:9.9p1-25.0.1.el10_2 | ELSA-2026-47757 | Jul 30, 2026 |
| openssh-keycat · ol 8 | 0:8.0p1-30.0.1.el8_10 | ELSA-2026-47755 | Jul 31, 2026 |
| openssh-keycat · ol 9 | 0:9.9p1-9.0.1.el9_8 | ELSA-2026-47756 | Aug 6, 2026 |
| openssh-keycat-debuginfo · amzn 2023 | 9.9p1-10.amzn2023.0.1 | ALAS2023-2026-2031 | Aug 3, 2026 |
| openssh-keysign · almalinux 10 | 9.9p1-25.el10_2.alma.1 | ALSA-2026:47757 | Jul 29, 2026 |
| openssh-keysign · ol 10 | 0:9.9p1-25.0.1.el10_2 | ELSA-2026-47757 | Jul 30, 2026 |
| openssh-ldap · RHEL 8 | 0:8.0p1-30.el8_10 | RHSA-2026:47755 | Jul 31, 2026 |
| openssh-ldap · almalinux 8 | 8.0p1-30.el8_10 | ALSA-2026:47755 | Jul 29, 2026 |
| openssh-ldap · ol 8 | 0:8.0p1-30.0.1.el8_10 | ELSA-2026-47755 | Jul 31, 2026 |
| openssh-server · RHEL 8 | 0:8.0p1-30.el8_10 | RHSA-2026:47755 | Jul 31, 2026 |
| openssh-server · RHEL 9 | 0:9.9p1-9.el9_8 | RHSA-2026:47756 | Jul 31, 2026 |
| openssh-server · almalinux 10 | 9.9p1-25.el10_2.alma.1 | ALSA-2026:47757 | Jul 29, 2026 |
| openssh-server · almalinux 8 | 8.0p1-30.el8_10 | ALSA-2026:47755 | Jul 29, 2026 |
| openssh-server · almalinux 9 | 9.9p1-9.el9_8.alma.1 | ALSA-2026:47756 | Jul 29, 2026 |
| openssh-server · amzn 2023 | 9.9p1-10.amzn2023.0.1 | ALAS2023-2026-2031 | Aug 3, 2026 |
| openssh-server · ol 10 | 0:9.9p1-25.0.1.el10_2 | ELSA-2026-47757 | Jul 30, 2026 |
| openssh-server · ol 8 | 0:8.0p1-30.0.1.el8_10 | ELSA-2026-47755 | Jul 31, 2026 |
| openssh-server · ol 9 | 0:9.9p1-9.0.1.el9_8 | ELSA-2026-47756 | Aug 6, 2026 |
| openssh-server-debuginfo · amzn 2023 | 9.9p1-10.amzn2023.0.1 | ALAS2023-2026-2031 | Aug 3, 2026 |
| openssh-sk-dummy · amzn 2023 | 9.9p1-10.amzn2023.0.1 | ALAS2023-2026-2031 | Aug 3, 2026 |
| openssh-sk-dummy-debuginfo · amzn 2023 | 9.9p1-10.amzn2023.0.1 | ALAS2023-2026-2031 | Aug 3, 2026 |
| pam_ssh_agent_auth · RHEL 8 | 0:0.10.3-7.30.el8_10 | RHSA-2026:47755 | Jul 31, 2026 |
| pam_ssh_agent_auth · RHEL 9 | 0:0.10.4-7.9.el9_8 | RHSA-2026:47756 | Jul 31, 2026 |
| pam_ssh_agent_auth · almalinux 8 | 0.10.3-7.30.el8_10 | ALSA-2026:47755 | Jul 29, 2026 |
| pam_ssh_agent_auth · almalinux 9 | 0.10.4-7.9.el9_8.alma.1 | ALSA-2026:47756 | Jul 29, 2026 |
| pam_ssh_agent_auth · amzn 2023 | 0.10.4-9.10.amzn2023.0.1 | ALAS2023-2026-2031 | Aug 3, 2026 |
| pam_ssh_agent_auth · ol 8 | 0:0.10.3-7.30.0.1.el8_10 | ELSA-2026-47755 | Jul 31, 2026 |
| pam_ssh_agent_auth · ol 9 | 0:0.10.4-7.9.0.1.el9_8 | ELSA-2026-47756 | Aug 6, 2026 |
| pam_ssh_agent_auth-debuginfo · amzn 2023 | 0.10.4-9.10.amzn2023.0.1 | ALAS2023-2026-2031 | Aug 3, 2026 |
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