CVE-2026-66822 — .NET Information Disclosure Vulnerability

Executive Summary

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

Overview

5.9

CVSS MEDIUM

Important

MS Severity

Not Exploited

MS Exploit Status

Less Likely

MS Exploit Likelihood

Category Information Disclosure

Weakness CWE-201: Insertion of Sensitive Information Into Sent Data

Released Oct 13 2026

Last Updated Oct 13 2026

Publicly Disclosed No

CISA KEV Not Listed

Known Exploits None Known

CVSS Vector

ATTACK VECTOR

Network

ATTACK COMPLEXITY

High

PRIVILEGES REQUIRED

None

USER INTERACTION

None

SCOPE

Unchanged

CONFIDENTIALITY

High

INTEGRITY

None

AVAILABILITY

None

EXPLOIT CODE MATURITY

Unproven

REMEDIATION LEVEL

Official Fix

REPORT CONFIDENCE

Confirmed

Temporal Score: 5.2

EPSS Score

No EPSS score available for this CVE.

View on FIRST.org

Affected Products

14 affected products

Product	KB Article	Severity	Impact	Restart Required
.NET 10.0 installed on Linux	`5130036 (Security Update)`	Important	Information Disclosure	Unknown
.NET 10.0 installed on Mac OS	`5130036 (Security Update)`	Important	Information Disclosure	Unknown
.NET 10.0 installed on Windows	`5130036 (Security Update)`	Important	Information Disclosure	Unknown
.NET 11.0 installed on Linux	`Release Notes (Security Update)`	Important	Information Disclosure	Unknown
.NET 11.0 installed on Mac OS	`Release Notes (Security Update)`	Important	Information Disclosure	Unknown
.NET 11.0 installed on Windows	`Release Notes (Security Update)`	Important	Information Disclosure	Unknown
.NET 8.0 installed on Linux	`5130034 (Security Update)`	Important	Information Disclosure	Unknown
.NET 8.0 installed on Mac OS	`5130034 (Security Update)`	Important	Information Disclosure	Unknown
.NET 8.0 installed on Windows	`5130034 (Security Update)`	Important	Information Disclosure	Unknown
.NET 9.0 installed on Linux	`5130035 (Security Update)`	Important	Information Disclosure	Unknown
.NET 9.0 installed on Mac OS	`5130035 (Security Update)`	Important	Information Disclosure	Unknown
.NET 9.0 installed on Windows	`5130035 (Security Update)`	Important	Information Disclosure	Unknown
Microsoft Visual Studio 2022 version 17.14	`Release Notes (Security Update)`	Important	Information Disclosure	Yes
Microsoft Visual Studio 2026 version 18.10	`Release Notes (Security Update)`	Important	Information Disclosure	Yes

Patches

4 patches

Article	Type	Restart
`5130036`	Security Update	Unknown
`Release Notes`	Security Update	Unknown
`5130034`	Security Update	Unknown
`5130035`	Security Update	Unknown

Exploits & PoC

No public exploit or PoC has been linked for this CVE yet. When available, references are sourced from public repositories and may be unverified or non-functional — review carefully before use.

Detection Rules

No public Sigma or Nuclei detection rule has been mapped to this CVE yet. Coverage is concentrated on exploited / high-profile vulnerabilities; check SigmaHQ for updates.

Acknowledgments

caveeroo
l8BL
Attila.Cs(zerodaybugs.com) with https://zerodaybugs.com/
Anonymous
Harkenzo
Raffaello Tamagnini
Leandro Batista
Kevin Schmidt
Piotr Pietruszewski
Brent Woodard
Weeraphat Srisutham
Lucas Futures
Wenhan Zhou
jhanks
Ky0toFu

References

MSRC Advisory MITRE NVD