CVE-2026-34182: CMS AuthEnvelopedData Processing May Accept Forged Messages

Overview

Severity

Critical (CVSS 9.1)

CVSS Vector

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

Exploit Status

Not Exploited

Patch Tuesday

2026-Sep

Released

2026-09-08

Last Updated

2026-09-08

EPSS Score

0.43% (percentile: 36.8%)

Affected Products (6)

Developer Tools

• Microsoft Visual Studio 2022 version 17.14
• Microsoft Visual Studio 2019 version 16.11 (includes 16.0 - 16.10)
• Microsoft Visual Studio 2017 version 15.9 (includes 15.0 - 15.8)
• Microsoft Visual Studio 2026 version 18.9

Open Source Software

• azl3 edk2 20240524git3e722403cd16-17 on Azure Linux 3.0
• azl3 openssl 3.3.5-5 on Azure Linux 3.0

Security Updates (4)

• Release Notes
• Release Notes
• Release Notes
• Release Notes

Acknowledgments

PatrickD [GER/BW]

Revision History

• 2026-09-08: Information published.
• 2026-06-16: Information published.
• 2026-06-18: Information published.
• 2026-06-23: Information published.
• 2026-08-07: Information published.
• 2026-09-08: Affected software updated with new package information.