CVE intelligence

CVE-2026-55200

Vulnerability intelligence

Published Jun 17, 2026Sources checked Sep 28, 2026

8.3HIGHCVSS out of 10

What this means

Review the available evidence

CVE-2026-55200 and is rated High severity with a CVSS score of 8.3. It is not in the current CISA KEV record we collected. That does not prove exploitation has not occurred.

CISA KEVNot listedBased on the latest collected catalog

EPSS0.8%Estimated 30-day exploitation probability

Ransomware useNot markedCISA KEV ransomware field

Threat actors0Source-linked actor relationships

Overview

What is CVE-2026-55200?

libssh2 through 1.11.1, fixed in commit 7acf3df contains an out-of-bounds write vulnerability in ssh2_transport_read() that fails to enforce upper bounds on packet_length field. Remote attackers can send crafted SSH packets with excessively large packet_length values to corrupt heap memory and achieve remote code execution.