Double Free in Openbsd Openssh
CVE-2026-55653
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 vali…
Vulnerability class: Double Free
EPSS: 0.002 (16.2th percentile) — read the EPSS interpretation.
CVSS v3 metric
CVSS v3 base score 4.3 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:L.
Affected products
- Openbsd Openssh
- Red Hat Enterprise Linux 10 — versions 0:9.9p1-25.el10_2
- Red Hat Enterprise Linux 6
- Red Hat Enterprise Linux 7
- Red Hat Enterprise Linux 8 — versions 0:8.0p1-30.el8_10
- Red Hat Enterprise Linux 9 — versions 0:9.9p1-9.el9_8
- Red Hat Hardened Images — versions 10.3p1-6.hum1
- Red Hat Openshift Container Platform 4
- Redhat Enterprise_linux — versions 6.0, 7.0, 8.0
- Redhat Hardened_images
Weakness classification (CWE)
References
- secalert@redhat.com (x_refsource_REDHAT, vdb-entry, Vendor Advisory)
- secalert@redhat.com (x_refsource_REDHAT, issue-tracking, Exploit, Issue Tracking, Vendor Advisory)
- secalert@redhat.com (x_refsource_REDHAT, vendor-advisory)
- secalert@redhat.com (x_refsource_REDHAT, vendor-advisory)
- secalert@redhat.com (x_refsource_REDHAT, vendor-advisory)
- secalert@redhat.com (x_refsource_REDHAT, vendor-advisory)
Frequently asked questions
- What is CVE-2026-55653?
- CVE-2026-55653 is a medium-severity vulnerability in Openbsd Openssh, classified under Double Free. CVSS score: 4.3/10. Published 2026-06-23.
- How severe is CVE-2026-55653?
- Medium severity. CVSS v3 base score is 4.3 out of 10.