CVE-2026-40372

Asp.Net Core vulnerability

CVSS

9.1

EPSS

11.2%

EPSS pct

96th

Exploited

No known

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

Affected vendor

Microsoft

Affected product

Asp.Net Core

CVSS vector

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

Weakness type (CWE)

CWE-347 — Improper Verification of Cryptographic Signature

Published

2026-04-21

Risk analysis

Based on its CVSS vector, this vulnerability is exploitable over the network, low attack complexity, requiring no privileges, no user interaction. Successful exploitation leads to high impact to confidentiality, high impact to integrity.

Its EPSS score of 11.2% reflects a moderate probability of exploitation activity in the wild over the next 30 days, placing it above 96% of all scored CVEs.

Check your external exposure to CVE-2026-40372

Confirm whether Microsoft Asp.Net Core is running on any internet-facing host or subdomain.
Match discovered service fingerprints against the version affected by CVE-2026-40372.
Prioritise remediation if the asset is public, business-critical, or near authentication/payment flows.

How ThreatPort helps with CVE-2026-40372

ThreatPort's external attack surface scanner checks your internet-facing assets — agentlessly, from the outside in — for the exposed services and versions that CVE-2026-40372 affects, then prioritises the finding by real risk using CISA KEV and FIRST.org EPSS.

Run a free external exposure scan

Are you exposed to CVE-2026-40372?

Run an instant, non-intrusive external scan to check your attack surface for CVE-2026-40372.

Start free scan

No credit card. Agentless.

Related vulnerabilities

Unified Threat Management Firewall vulnerability

CRITICAL

CVE-2019-9194

Elfinder vulnerability