Reference page — cumulative record through Monday, October 19, 2026 UTC. Reference pages update as the archive grows; only dated daily editions are immutable pages of record.

CVE-2026-55653

CVE-2026-55653MEDIUM

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   .0073   53.4     —

AFFECTED
  Product                                                         Versions     Fixed
  Red Hat Enterprise Linux 10                                     unspecified  0:9.9p1-25.el10_2
  Red Hat Enterprise Linux 10.0 Extended Update Support           unspecified  0:9.9p1-7.el10_0.5
  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 Enterprise Linux 9.4 Update Services for SAP Solutions  unspecified  0:8.7p1-38.el9_4.10
  Red Hat Enterprise Linux 9.6 Extended Update Support            unspecified  0:8.7p1-45.el9_6.5
  Red Hat Hardened Images                                         unspecified  10.3p1-6.hum1
  Red Hat OpenShift AI 3.0                                        unspecified  1791818590
  + 44 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).
  Aug 24  EXPLOIT PUBLISHED — CVE-2026-55653 (Red Hat Enterprise Linux 10). Public exploit reference added.
  Aug 25  EXPLOIT PUBLISHED — CVE-2026-55653 (Red Hat Enterprise Linux 10). Public exploit reference added.
  Aug 31  EXPLOIT PUBLISHED — CVE-2026-55653 (Red Hat Enterprise Linux 10). Public exploit reference added.
  Sep 1   EXPLOIT PUBLISHED — CVE-2026-55653 (Red Hat Enterprise Linux 10). Public exploit reference added.
  Oct 7   EXPLOIT PUBLISHED — CVE-2026-55653 (Red Hat Enterprise Linux 10). Public exploit reference added.
  Oct 12  EXPLOIT PUBLISHED — CVE-2026-55653 (Red Hat Enterprise Linux 10). Public exploit reference added.
  Oct 14  EXPLOIT PUBLISHED — CVE-2026-55653 (Red Hat Enterprise Linux 10). Public exploit reference added.

CWE-415 · CNA: redhat · CVSS v3.1 · 48 references · NVD status: Modified

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 — 12 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).
August 24, 2026	EXPLOIT PUBLISHED	EXPLOIT PUBLISHED — CVE-2026-55653 (Red Hat Enterprise Linux 10). Public exploit reference added.
August 25, 2026	EXPLOIT PUBLISHED	EXPLOIT PUBLISHED — CVE-2026-55653 (Red Hat Enterprise Linux 10). Public exploit reference added.
August 31, 2026	EXPLOIT PUBLISHED	EXPLOIT PUBLISHED — CVE-2026-55653 (Red Hat Enterprise Linux 10). Public exploit reference added.
September 1, 2026	EXPLOIT PUBLISHED	EXPLOIT PUBLISHED — CVE-2026-55653 (Red Hat Enterprise Linux 10). Public exploit reference added.
October 7, 2026	EXPLOIT PUBLISHED	EXPLOIT PUBLISHED — CVE-2026-55653 (Red Hat Enterprise Linux 10). Public exploit reference added.
October 12, 2026	EXPLOIT PUBLISHED	EXPLOIT PUBLISHED — CVE-2026-55653 (Red Hat Enterprise Linux 10). Public exploit reference added.
October 14, 2026	EXPLOIT PUBLISHED	EXPLOIT PUBLISHED — CVE-2026-55653 (Red Hat Enterprise Linux 10). Public exploit reference added.

Affected

Affected products and packages — 54 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 10.0 Extended Update Support	—	—	0:9.9p1-7.el10_0.5
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 Enterprise Linux 9.4 Update Services for SAP Solutions	—	—	0:8.7p1-38.el9_4.10
Red Hat	Red Hat Enterprise Linux 9.6 Extended Update Support	—	—	0:8.7p1-45.el9_6.5
Red Hat	Red Hat Hardened Images	—	—	10.3p1-6.hum1
Red Hat	Red Hat OpenShift AI 3.0	—	—	1791818590
Red Hat	Red Hat OpenShift AI 3.0	—	—	1791818589
Red Hat	Red Hat OpenShift AI 3.0	—	—	1791818505
Red Hat	Red Hat OpenShift AI 3.0	—	—	1791818496
Red Hat	Red Hat OpenShift AI 3.0	—	—	1791818502
Red Hat	Red Hat OpenShift AI 3.2	—	—	1791818602
Red Hat	Red Hat OpenShift AI 3.2	—	—	1791818598
Red Hat	Red Hat OpenShift AI 3.2	—	—	1791818512
Red Hat	Red Hat OpenShift AI 3.2	—	—	1791818587
Red Hat	Red Hat OpenShift AI 3.2	—	—	1791818778
Red Hat	Red Hat OpenShift AI 3.2	—	—	1791818512
Red Hat	Red Hat OpenShift AI 3.3	—	—	1791818782
Red Hat	Red Hat OpenShift AI 3.3	—	—	1791818782
Red Hat	Red Hat OpenShift AI 3.3	—	—	1791818627
Red Hat	Red Hat OpenShift AI 3.3	—	—	1791818790
Red Hat	Red Hat OpenShift AI 3.3	—	—	1791818874
Red Hat	Red Hat OpenShift AI 3.3	—	—	1791818792
Red Hat	Red Hat OpenShift AI 3.3	—	—	1791818662
Red Hat	Red Hat OpenShift AI 3.3	—	—	1791818877
Red Hat	Red Hat OpenShift AI 3.4	—	—	1791883722
Red Hat	Red Hat OpenShift AI 3.4	—	—	1791881612
Red Hat	Red Hat OpenShift AI 3.4	—	—	1791885618
Red Hat	Red Hat OpenShift AI 3.4	—	—	1791881487
Red Hat	Red Hat OpenShift AI 3.4	—	—	1791881732
Red Hat	Red Hat OpenShift AI 3.4	—	—	1791883315
Red Hat	Red Hat OpenShift AI 3.4	—	—	1791881486
Red Hat	Red Hat OpenShift AI 3.4	—	—	1791881769
Red Hat	Red Hat OpenShift AI 3.4	—	—	1791885505
Red Hat	Red Hat OpenShift AI 3.5	—	—	1791819252
Red Hat	Red Hat OpenShift AI 3.5	—	—	1791818749
Red Hat	Red Hat OpenShift AI 3.5	—	—	1791819206
Red Hat	Red Hat OpenShift AI 3.5	—	—	1791818979
Red Hat	Red Hat OpenShift AI 3.5	—	—	1791819123
Red Hat	Red Hat OpenShift AI 3.5	—	—	1791818901
Red Hat	Red Hat OpenShift AI 3.5	—	—	1791820333
Red Hat	Red Hat OpenShift AI 3.5	—	—	1791819495
Red Hat	Red Hat OpenShift AI 3.5	—	—	1791819104
Red Hat	Red Hat Update Infrastructure 5	—	—	1786435483
Red Hat	Red Hat Update Infrastructure 5	—	—	1786533529
Red Hat	Red Hat Update Infrastructure 5	—	—	1787135742
Red Hat	Red Hat Update Infrastructure 5	—	—	1787241260
Red Hat	Red Hat Enterprise Linux 6	—	—	—
Red Hat	Red Hat Enterprise Linux 7	—	—	—
Red Hat	Red Hat OpenShift Container Platform 4	—	—	—
Red Hat	Red Hat OpenShift Container Platform 4	—	—	—

Weaknesses

CWE-415

References (48)

Authoritative record: CVE-2026-55653 at cve.org

Vendors: red hat

Weaknesses: CWE-415

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 Monday, October 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.