CVE-2026-54780

CoreWCF: WS-Security Reference DigestMethod Algorithm-Suite Bypass

Workarounds

None

CoreWCF’s WS-Security 1.0 receive pipeline validates the SignatureMethod of an incoming ds:SignedInfo against the configured SecurityAlgorithmSuite, but does not validate the DigestMethod declared on each ds:Reference. As a result, a sender can populate ds:SignedInfo with SignatureMethod values the suite accepts (for example rsa-sha256 under Basic256Sha256) while declaring a per-reference DigestMethod the suite rejects (for example http://www.w3.org/2000/09/xmldsig#sha1). The signature is then verified where it permits SHA-1 digests, and the message is accepted.

The application uses a cryptographic algorithm known to have weaknesses, such as MD5, SHA-1, or DES. Typical impact: compromised confidentiality or integrity of protected data.

CVE-2026-54780 has a CVSS score of 3.7 (Low). The vector is network-reachable, no privileges required, and no user interaction. A CVSS score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether this affects your application depends on whether the vulnerable code is present and reachable in your environment. A fixed version is available (1.8.1, 1.9.1); upgrading removes the vulnerable code path.

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Fixed in CoreWCF v1.8.1 and v1.9.1

1. What is CVE-2026-54780? CVE-2026-54780 is a low-severity use of a broken or risky cryptographic algorithm vulnerability in CoreWCF.Primitives (nuget), affecting versions < 1.8.1. It is fixed in 1.8.1, 1.9.1. The application uses a cryptographic algorithm known to have weaknesses, such as MD5, SHA-1, or DES.
2. How severe is CVE-2026-54780? CVE-2026-54780 has a CVSS score of 3.7 (Low). This score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether it represents real risk in your environment depends on whether the vulnerable code is present and reachable.
3. Which versions of CoreWCF.Primitives are affected by CVE-2026-54780? CoreWCF.Primitives (nuget) versions < 1.8.1 is affected.
4. Is there a fix for CVE-2026-54780? Yes. CVE-2026-54780 is fixed in 1.8.1, 1.9.1. Upgrade to this version or later.
5. Is CVE-2026-54780 exploitable, and should I be worried? Whether CVE-2026-54780 is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk. Get a demo
6. What actually determines whether CVE-2026-54780 is exploitable, and how bad it is? Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.
7. How do I fix CVE-2026-54780?
   • Upgrade CoreWCF.Primitives to 1.8.1 or later
   • Upgrade CoreWCF.Primitives to 1.9.1 or later

Other vulnerabilities in CoreWCF.Primitives