What is CVE-2026-40372?
Improper verification of cryptographic signature in ASP.NET Core allows an unauthorized attacker to elevate privileges over a network.
The record classifies CVE-2026-40372 under weakness class CWE-347. Its CVSS v3 base vector states that the flaw is reachable remotely over the network, needs no prior authentication, needs no user interaction, and has high impact on confidentiality, integrity. 2 affected-product entries are recorded, across 1 vendor, listed below. The identifier was first published 197 days ago.
Severity and exploitation probability
- CVSS v3.1 base score
- 9.1 — CRITICAL
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N - EPSS (FIRST)
- 0.8% probability of exploitation in the next 30 days, higher than 56.1% of all scored CVEs
- CISA KEV
- Not listed in the CISA Known Exploited Vulnerabilities catalog
- Threadlinqs priority
- 6.8/10 — a Threadlinqs composite of the CVSS base score, the EPSS percentile and public exploit availability
- Published
- 2026-04-21, last modified 2026-09-25
Is CVE-2026-40372 being exploited?
It currently carries a trending score of 19 in the Threadlinqs vulnerability feed.
Affected products and versions
- Microsoft: ASP.NET Core 10.0, Visual Studio 2026 version 18.5
Affected software packages:
nuget:Microsoft.AspNetCore.DataProtection— patched in 10.0.7
How to fix CVE-2026-40372
The record marks a vendor fix as available for CVE-2026-40372. Fixed versions are recorded for 1 package: nuget:Microsoft.AspNetCore.DataProtection 10.0.7. Vendor advisory: https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-40372. Apply the vendor fix referenced above to every affected product listed in this record, then confirm the running version against the vendor advisory.
Threat activity tracking CVE-2026-40372
2 tracked threats in the Threadlinqs corpus reference CVE-2026-40372, either in the campaign’s CVE list or as an indicator on the campaign record.
Sources
Enriched from CVE.org, FIRST EPSS, GitHub Security Advisories. Last verified by Threadlinqs on .