CVE-2026-35199: SymCrypt SymCryptXmssSign function - Heap overflow via 64->32-bit leaf-count truncation

Overview

Severity

Medium (CVSS 6.1)

CVSS Vector

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

Exploit Status

Not Exploited

Patch Tuesday

2026-Apr

Released

2026-04-17

EPSS Score

0.06% (percentile: 17.3%)

Affected Products (1)

Other

• 21216-17084

Revision History

• 2026-04-17: Information published.