CVE-2026-40372: ASP.NET Core Elevation of Privilege Vulnerability

Critical severity · published Apr 21, 2026

CVE-2026-40372

ASP.NET Core Elevation of Privilege Vulnerability

9.1

CVSS

11.2%

EPSS

On KEV

Description

Improper verification of cryptographic signature in ASP.NET Core allows an unauthorized attacker to elevate privileges over a network.

CVSS vector

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

Attack vector

Network

Complexity

Low

Privileges

None

User interaction

None

Confidentiality

High

Integrity

High

Availability

None

Scope

Unchanged

Exploitation

Is it being used?

Exploit prediction (EPSS)11.2% · higher than 96% of CVEs

Exploited in the wildNo evidence yet

CISA KEVNot listed

Ransomware campaign useNot known

Affected products

Which versions

ASP.NET Core 10.0 · Microsoft

10.0 before 10.0.7 · source: vendor

Microsoft Visual Studio 2026 version 18.5 · Microsoft

18.5.0 before 18.5.2 · source: vendor

Asp.net Core · Microsoft

10.0.0 before 10.0.7 · source: NVD

In the news

VulnerabilityCritical

Microsoft Patches Critical ASP.NET Core CVE-2026-40372 Privilege Escalation Bug

Microsoft has released out-of-band updates to address a security vulnerability in ASP.NET Core that could allow an attacker to escalate privileges. The vulnerability, tracked as CVE-2026-40372, carries a CVSS score of 9.1 out of 10.0. It's rated Important in severity. An anonymous researcher has been credited with discovering and reporting the flaw. "Improper verification of cryptographic

CVE-2026-40372

Apr 22, 2026·The Hacker News

Affected product

ASP.NET Core 10.0

Microsoft

All ASP.NET Core 10.0 CVEs

References

NVD

https://nvd.nist.gov/vuln/detail/CVE-2026-40372

CVE.org

https://www.cve.org/CVERecord?id=CVE-2026-40372

Vendor Advisory