Microsoft Windows CryptoAPI Spoofing Vulnerability

Microsoft Windows CryptoAPI (Crypt32.dll) contains a spoofing vulnerability in the way it validates Elliptic Curve Cryptography (ECC) certificates. An attacker could exploit the vulnerability by using a spoofed code-signing certificate to sign a malicious executable, making it appear the file was from a trusted, legitimate source. A successful exploit could also allow the attacker to conduct man-in-the-middle attacks and decrypt confidential information on user connections to the affected software. The vulnerability is also known under the moniker of CurveBall.

Published 19 Oct 2026Updated 19 Oct 202620 sources
CVSS 8.1 ✓ VERIFIED REFERENCE△ CISA KEV

Source timeline

Discovered through CISA Known Exploited VulnerabilitiesView source ↗
Added to CISA Known Exploited Vulnerabilities catalogView source ↗
Added to CISA Known Exploited Vulnerabilities catalogView source ↗
Added to CISA Known Exploited Vulnerabilities catalogView source ↗
Added to CISA Known Exploited Vulnerabilities catalogView source ↗