Selection of Less-Secure Algorithm During Negotiation ('Algorithm Downgrade') Affecting corewcf.primitives package, versions [,1.8.1)[1.9.0,1.9.1)
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- published21 Jun 2026
- disclosed19 Jun 2026
- creditUnknown
Introduced: 19 Jun 2026
NewCVE-2026-54780 (opens in a new tab)How to fix?
Upgrade CoreWCF.Primitives to version 1.8.1, 1.9.1 or higher.
Overview
CoreWCF.Primitives is a port of the service side of Windows Communication Foundation (WCF) to .NET Core. The goal of this project is to enable existing WCF services to move to .NET Core.
Affected versions of this package are vulnerable to Selection of Less-Secure Algorithm During Negotiation ('Algorithm Downgrade') through the WSSecurityOneDotZeroReceiveSecurityHeader.VerifySignatureAsync path in CoreWCF.Security. An attacker can get a signed SOAP message accepted by supplying a ds:Reference DigestMethod URI that the configured SecurityAlgorithmSuite does not support. This lets a sender use a digest algorithm outside the suite’s advertised policy, causing the receiver to trust and process a signature that should have been rejected.