CVE-2026-66822: .NET Information Disclosure Vulnerability

Overview

Severity
Medium (CVSS 5.9)
CVSS Vector
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N/E:U/RL:O/RC:C
Category
Information Disclosure
Exploit Status
Not Exploited
Exploitation Likelihood
Less Likely
Patch Tuesday
2026-Oct
Released
2026-10-13

Description

Insertion of sensitive information into sent data in .NET allows an unauthorized attacker to disclose information over a network.

FAQ

What type of information could be disclosed by this vulnerability? Exploiting this vulnerability could allow the disclosure of credentials. According to the CVSS metric, the attack complexity is high (AC:H). What does this mean for this vulnerability? An attacker would need specific conditions to be in place (i.e. particular protocol settings, or configurations, etc.) before an attack could succeed, which reduces the likelihood of widespread or opportunistic exploitation.

Affected Products (14)

Developer Tools

  • .NET 11.0 installed on Windows
  • .NET 11.0 installed on Linux
  • .NET 11.0 installed on Mac OS
  • .NET 10.0 installed on Windows
  • .NET 10.0 installed on Linux
  • .NET 10.0 installed on Mac OS
  • .NET 8.0 installed on Linux
  • .NET 8.0 installed on Windows
  • .NET 8.0 installed on Mac OS
  • .NET 9.0 installed on Linux
  • .NET 9.0 installed on Mac OS
  • Microsoft Visual Studio 2022 version 17.14
  • .NET 9.0 installed on Windows
  • Microsoft Visual Studio 2026 version 18.10

Security Updates (6)

Acknowledgments

<a href="https://caveeroo.dev/">caveeroo</a> with <a href="https://www.tarlogic.com/">Tarlogic</a>, <a href="https://www.linkedin.com/in/jiheun-kim/">l8BL</a> with <a href="https://www.enki.co.kr/">ENKI WhiteHat</a>, Attila.Cs(zerodaybugs.com) with https://zerodaybugs.com/, Anonymous, Harkenzo, Raffaello Tamagnini, <a href="https://www.linkedin.com/in/leandrosbatista21/">Leandro Batista</a>, <a href="https://www.linkedin.com/in/kevin-sch/">Kevin Schmidt</a>, Piotr Pietruszewski, Anonymous, <a href="https://x.com/crusader_sec">Brent Woodard</a> with <a href="https://crusaderproxy.com/">Crusader Security, LLC</a>, <a href="https://linkedin.com/in/weeraphat-srisutham">Weeraphat Srisutham</a>, Lucas Futures, <a href="https://www.linkedin.com/in/wenhan-zhou-4a949b21a/">Wenhan Zhou</a>, jhanks, Anonymous, <a href="https://x.com/ky0tofu">Ky0toFu</a>

Revision History

  • 2026-10-13: Information published.