CVE-2026-54773 CoreWCF: WS-Security signature substitution via document-wide Signature lookup
An attacker can bypass WS-Security signature verification in CoreWCF by manipulating SOAP headers, allowing unauthorized access to protected services.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-54773?
CVE-2026-54773 is a medium-severity vulnerability in CoreWCF, published on 8 Jul 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official description
CoreWCF is a port of the service side of Windows Communication Foundation (WCF) to .NET Core. Prior to 1.8.1 and 1.9.1, CoreWCF WS-Security signature verification performs a document-wide ds:Signature lookup, allowing an unauthenticated remote attacker to place a SOAP header before wsse:Security and cause WSSecurityOneDotZeroReceiveSecurityHeader to verify an attacker-supplied signature instead of the security header signature. This issue is fixed in versions 1.8.1 and 1.9.1.
Weakness: CWE-347
Which versions are affected by CVE-2026-54773?
4 open source packages ship an affected version, including CoreWCF.Primitives.
| Package | Affected | Fixed in |
|---|---|---|
CoreWCF.Primitives NuGet | All versions | 1.8.1 |
CoreWCF.Primitives NuGet | All versions | 1.8.1 |
CoreWCF.Primitives NuGet | From 1.9.0 | 1.9.1 |
CoreWCF.Primitives NuGet | From 1.9.0 | 1.9.1 |
How do I fix CVE-2026-54773?
Upgrade CoreWCF.Primitives to a fixed version for your release line: 1.8.1 or 1.9.1.
Is CVE-2026-54773 being exploited?
There is no known exploitation of CVE-2026-54773 in the wild and no public exploit code.
Sources
Also known as GHSA-jc6x-rj79-w4mx.