CVE-2026-55653

MEDIUM
MEDIUM Priority: 0.02 BB Relevance: 59/100
Published: 2026-06-23 Modified: 2026-10-26 First seen: 2026-10-29 Status: active

Attack Surface

Network Low Complexity No Auth

CVSS Vector Breakdown

AV: Network
AC: Low
PR: None
UI: Required
S: Unchanged
C: None
I: None
A: Low

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).

Weakness Classification (1)

Bug Bounty Relevance

59 / 100
✓ Network accessible
✓ No authentication
✓ Low complexity

CVSS Score

4.3 / 10.0 v3.1
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:L

EPSS — Exploitation Probability

0.53%
Raw Score 0.005300
Percentile 44.7%
Date 2026-10-28

Intelligence Sources

mitre ref →
nvd ref →