PT-2026-40207 · Microsoft · Windows Cryptographic Services+1

Published 2026-05-12 · Updated 2026-05-12 · CVE-2026-40377

Positive Technologies (AI Summary)

CVSS v3.1

7.8

High

Base vector

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

Name of the Vulnerable Software and Affected Versions Windows Cryptographic Services (affected versions not specified)

Description A heap-based buffer overflow in Windows Cryptographic Services allows an authorized attacker to elevate privileges locally. A heap-based buffer overflow occurs when a program writes more data to a heap-allocated memory block than it can hold, potentially leading to arbitrary code execution or privilege escalation.

Recommendations At the moment, there is no information about a newer version that contains a fix for this vulnerability.

Heap Based Buffer Overflow

Weakness Enumeration

CWE-122

Related Identifiers

BDU:2026-06871

CVE-2026-40377

Affected Products

Windows

Windows Cryptographic Services

References · 6

• https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-40377 · Vendor Advisory
• http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2026-40377 · Security Note
• https://bdu.fstec.ru/vul/2026-06871 · Security Note
• https://msrc.microsoft.com/update-guide/en-US/advisory/CVE-2026-40377 · Vendor Advisory
• https://nvd.nist.gov/vuln/detail/CVE-2026-40377 · Security Note
• https://twitter.com/windowsforum/status/2054284699229421954 · Twitter Post