CVE-2026-66035: libssh2 Heap Buffer Overflow via ETM Cipher Negotiation

Overview

Severity

High (CVSS 7.5)

CVSS Vector

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

Exploit Status

Not Exploited

Patch Tuesday

2026-Jul

Released

2026-07-26

EPSS Score

0.32% (percentile: 24.4%)

Affected Products (2)

Other

• 21431-17084
• 21559-17084

Revision History

• 2026-07-26: Information published.