Reference page — cumulative record through Wednesday, August 19, 2026 UTC. Reference pages update as the archive grows; only dated daily editions are immutable pages of record.
Red Hat Red Hat Enterprise Linux 10 — 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
AV AC PR UI S C I A CVSS EPSS %ile KEV
N L N R U N N H 6.5 .0029 21.5 —
AFFECTED
Product Versions Fixed
Red Hat Enterprise Linux 10 unspecified 0:9.9p1-25.el10_2
Red Hat Enterprise Linux 8 unspecified 0:8.0p1-30.el8_10
Red Hat Enterprise Linux 8 unspecified 0:8.0p1-30.el8_10
Red Hat Enterprise Linux 9 unspecified 0:9.9p1-9.el9_8
Red Hat Enterprise Linux 9 unspecified 0:9.9p1-9.el9_8
Red Hat Hardened Images unspecified 10.3p1-6.hum1
Red Hat Update Infrastructure 5 unspecified 1786435483
Red Hat Update Infrastructure 5 unspecified 1786533529
Red Hat Enterprise Linux 6 unspecified —
Red Hat Enterprise Linux 7 unspecified —
+ 1 more
TIMELINE
Jun 16 Reserved by redhat
Jun 23 EXPLOIT PUBLISHED — CVE-2026-55653 (Red Hat Enterprise Linux 10). Public exploit reference added.
Jun 23 Published (CNA: redhat)
Aug 12 EXPLOIT PUBLISHED — CVE-2026-55653 (Red Hat Enterprise Linux 10). Public exploit reference added.
Aug 12 RESCORED — CVE-2026-55653 (Red Hat Enterprise Linux 10). CVSS 4.3 → 6.5 (NVD).
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).
Lifecycle
Complete event history — 5 events, chronological
| Date | Event | Detail |
|---|
| June 16, 2026 | Reserved | Reserved by redhat |
| June 23, 2026 | EXPLOIT PUBLISHED | EXPLOIT PUBLISHED — CVE-2026-55653 (Red Hat Enterprise Linux 10). Public exploit reference added. |
| June 23, 2026 | Published | Published (CNA: redhat) |
| August 12, 2026 | EXPLOIT PUBLISHED | EXPLOIT PUBLISHED — CVE-2026-55653 (Red Hat Enterprise Linux 10). Public exploit reference added. |
| August 12, 2026 | RESCORED | RESCORED — CVE-2026-55653 (Red Hat Enterprise Linux 10). CVSS 4.3 → 6.5 (NVD). |
Affected
Affected products and packages — 11 rows
| Vendor | Product / Package | Ecosystem | Version introduced | Fixed |
|---|
| Red Hat | Red Hat Enterprise Linux 10 | — | — | 0:9.9p1-25.el10_2 |
| Red Hat | Red Hat Enterprise Linux 8 | — | — | 0:8.0p1-30.el8_10 |
| Red Hat | Red Hat Enterprise Linux 8 | — | — | 0:8.0p1-30.el8_10 |
| Red Hat | Red Hat Enterprise Linux 9 | — | — | 0:9.9p1-9.el9_8 |
| Red Hat | Red Hat Enterprise Linux 9 | — | — | 0:9.9p1-9.el9_8 |
| Red Hat | Red Hat Hardened Images | — | — | 10.3p1-6.hum1 |
| Red Hat | Red Hat Update Infrastructure 5 | — | — | 1786435483 |
| Red Hat | Red Hat Update Infrastructure 5 | — | — | 1786533529 |
| Red Hat | Red Hat Enterprise Linux 6 | — | — | — |
| Red Hat | Red Hat Enterprise Linux 7 | — | — | — |
| Red Hat | Red Hat OpenShift Container Platform 4 | — | — | — |
About this page
This is a reference page, not a dated page of record. It assembles the complete lifecycle of CVE-2026-55653 from the CVE Program record, NVD enrichment, the CISA KEV catalog, EPSS, and OSV advisories. The box score's numbers (CVSS, EPSS, KEV status) are current as of Wednesday, August 19, 2026 UTC and are re-derived as the archive grows; only dated daily editions are immutable pages of record. The authoritative source for this identifier is cve.org.