CVE-2026-55653

Low

No strong exploitation signal.

CVSS base

4.3 MEDIUM

CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:L

EPSS — probability of exploitation (30 days)

0.3%

22.5th percentile

CISA KEV

Not listed

Weakness / dates

CWE-415

Published 2026-06-23 · modified 2026-09-01

CVSS breakdown

CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:L

Attack Vector	N	Network
Attack Complexity	L	Low
Privileges Required	N	None
User Interaction	R	Required
Scope	U	Unchanged
Confidentiality	N	None
Integrity	N	None
Availability	L	Low

Timeline

2026-06-23 — Published (NVD)
2026-09-01 — Last modified (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).

Affected

openbsd redhat

References

Official: NVD · CVE.org