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CWE-290Weakness · CWE-290

CVE-2026-54782

CRITICAL · 10.0 CVSS v3.1 Published 2026-07-08
Patch available
A vendor patch is available. No clean upgrade release — apply the published patch.
See remediation →
100/100
Remediation priority · Urgent
Remotely reachable No privileges Zero-click Patch available 6 weeks old

Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.

NVD · unedited
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 SAML 1.1 and SAML 2.0 token validation does not correctly resolve the issuer signing key or require signed tokens when IdentityConfiguration is used with federated bindings, allowing an unauthenticated remote attacker to impersonate any principal the trusted STS could issue. This issue is fixed in versions 1.8.1 and 1.9.1.

Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.

dbcve analysis · high confidence

CoreWCF versions prior to 1.8.1 and 1.9.1 contain a critical SAML token validation flaw where the issuer signing key is not correctly resolved and signed tokens are not required when IdentityConfiguration is used with federated bindings. This allows an unauthenticated remote attacker to forge SAML tokens and impersonate any principal that the trusted Security Token Service (STS) could issue.

MitigationUpgrade CoreWCF to version 1.8.1 or 1.9.1. If upgrading is not immediately possible, review and harden the IdentityConfiguration and federated binding settings to enforce signed token validation and proper issuer key resolution.

Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.

CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.

From the vector
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
None
Scope
Changed
Confidentiality
High
Integrity
High
Availability
None

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:N

Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.

dbcve checks

Work through these to decide whether this CVE applies to you.

  1. Determine installed CoreWCF version
    Inspect the CoreWCF assembly or NuGet package reference in your project to identify the exact version number. Compare this version against the fixed releases 1.8.1 and 1.9.1.
    Affected if The installed version is earlier than 1.8.1 or 1.9.1.
  2. Identify if IdentityConfiguration is in use
    Search your application configuration files and code for IdentityConfiguration or related security configuration classes that configure identity providers.
    Affected if IdentityConfiguration is present and configured in your CoreWCF deployment.
  3. Check for federated binding configuration
    Examine your service configuration for WSFederationHttpBinding or custom federated binding settings that integrate with a Security Token Service (STS).
    Affected if Federated bindings are configured to communicate with an STS.
  4. Inspect SAML token validation settings
    Review the SAML token validation configuration within your IdentityConfiguration or federation settings. Specifically check whether signed token enforcement is enabled and how the issuer signing key is resolved.
    Affected if Signed tokens are not required or the issuer signing key resolution appears misconfigured.

You are affected if your CoreWCF version is prior to 1.8.1/1.9.1 AND you use IdentityConfiguration with federated bindings, and your SAML token validation does not enforce signed tokens or correctly resolve issuer keys.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.

dbcve · scoped
Patch available Apply the vendor patch
Vendor patch github.com →
Interim mitigation

Upgrade CoreWCF to version 1.8.1 or 1.9.1. If upgrading is not immediately possible, review and harden the IdentityConfiguration and federated binding settings to enforce signed token validation and proper issuer key resolution.

Recommended fix High confidence

CoreWCF versions 1.8.1 or 1.9.1

  1. Identify the current CoreWCF version in use by checking the .csproj file or packages.config for CoreWCF package references
  2. Update the CoreWCF package reference to version 1.8.1 or 1.9.1 (preferably 1.9.1 for the latest stable fix) by editing the .csproj file: <PackageReference Include="CoreWCF.Primitives" Version="1.9.1" /> and <PackageReference Include="CoreWCF.Http" Version="1.9.1" />
  3. Run 'dotnet restore' to fetch the updated packages
  4. Rebuild the solution with 'dotnet build' to ensure compatibility with the new version
  5. Deploy the updated application to production environments
Caveat Review CoreWCF 1.8.x and 1.9.x release notes for any breaking changes; if coming from 1.x versions below 1.8, test SAML authentication thoroughly as this is a security fix that changes token validation behavior

Generated from the published advisory — verify against the referenced sources before acting.

Have this fixed Scoped from the published advisory
  • Consultation4.0 h
  • Implementation4.0 h
  • Testing8.0 h
  • Review / QA4.0 h
20.0 hours of engineering $3,440
Get the patch applied

An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $5,504.

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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2026-54782 in production — separate from our analysis above.

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What this is

A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.

What belongs here
  • Verified mitigations, workarounds, and config changes
  • Version or environment caveats, and links to real fixes
  • No weaponised exploit code, or anything meant to cause harm
  • No spam, self-promotion, credentials, or personal data