PT-2026-26608 · Microsoft · Winrm

Published 2026-03-20 · Updated 2026-05-03 · CVE-2026-4434

Positive Technologies (AI Summary)

CVSS v3.1

8.1

High

Base vector

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

Name of the Vulnerable Software and Affected Versions versions prior to 2026-4434

Description A flaw exists in the validation of certificates during PAM propagation WinRM connections. This allows a network attacker to conduct a man-in-the-middle attack by disabling TLS certificate verification. The issue involves improper certificate validation.

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

Improper Certificate Validation

Weakness Enumeration

CWE-295

Related Identifiers

CVE-2026-4434

Affected Products

Winrm

References · 5

• https://nvd.nist.gov/vuln/detail/CVE-2026-4434 · Security Note
• https://devolutions.net/security/advisories/DEVO-2026-0005 · Vendor Advisory
• https://twitter.com/HugoValters/status/2050855055742345714 · Twitter Post
• https://twitter.com/CVEnew/status/2035626981933428956 · Twitter Post
• https://twitter.com/TheHackerWire/status/2036136099362570741 · Twitter Post