CVE-2026-54779: CoreWCF SAML Token Replay Protection Is Vulnerability

Q: What is CVE-2026-54779?

CVE-2026-54779 is a security vulnerability in CoreWCF involving SAML token replay protection is inoperative under CWE-613: Insufficient Session Expiration.

Q: Which CoreWCF versions are affected?

Affected versions include releases prior to 1.8.1, 1.9.1 across affected packages: CoreWCF.Primitives.

Q: What version fixes CVE-2026-54779?

Upgrading to 1.8.1, 1.9.1 (or the latest patched release for your respective branch) resolves the vulnerability.

Q: Is CoreWCF.Primitives affected?

Yes, CoreWCF.Primitives is affected in releases prior to 1.8.1, 1.9.1. Upgrade your dependency to 1.8.1, 1.9.1 or later.

Q: What is the CVSS score of CVE-2026-54779?

CVE-2026-54779 has a CVSS v3.1 base score of 5.9 (MODERATE) with vector string CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:H/A:N.

Q: What CWE is associated with CVE-2026-54779?

CVE-2026-54779 is classified under CWE-613: Insufficient Session Expiration (According to WASC, "Insufficient Session Expiration is when a web site permits an attacker to reuse old session credentials or session IDs for authorization.").

Q: How can I check NuGet dependencies for CVE-2026-54779?

Run the dependency tree command: 'inspect dependencies for CoreWCF.Primitives'. This command lists direct and transitive dependencies in your build configuration so you can verify if a vulnerable version is resolved.

MODERATE

Advisory Identifier: GHSA-9jr3-rj99-8jq3

CVSS 5.9

CWE-613 CWE-294

Published 2026-06-19

Advisory Summary

CVE-2026-54779 is a MODERATE (CVSS 5.9) saml token replay protection is vulnerability (CWE-613: Insufficient Session Expiration) affecting CoreWCF libraries in the NuGet ecosystem. The issue involves saml token replay protection is inoperative. Remediation is available by upgrading affected packages to version 1.8.1, 1.9.1.

CVE-2026-54779 at a Glance

CVE Identifier CVE-2026-54779

GHSA Identifier GHSA-9jr3-rj99-8jq3

Severity MODERATE

CVSS v3.1 Base Score 5.9

CWE Classification CWE-613: Insufficient Session Expiration

Affected Product CoreWCF

Package Ecosystem NuGet

Published Date 2026-06-19

Last Updated 2026-06-19

Security Impact

CVSS: 5.9

The security impact metrics below are parsed directly from the CVSS v3.1 vector string (CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:H/A:N).

Attack Vector Network (AV:N)

Attack Complexity High (AC:H)

Privileges Required None (PR:N)

User Interaction None (UI:N)

Scope Unchanged (S:U)

Confidentiality None (C:N)

Integrity High (I:H)

Availability None (A:N)

How to Fix CVE-2026-54779

To remediate this vulnerability, upgrade all affected CoreWCF dependencies to a patched release. Both direct and transitive dependencies should be checked, as frameworks or security libraries may pull in vulnerable versions transitively.

CoreWCF.Primitives fixed: 1.8.1

Upgrade CoreWCF.Primitives to 1.8.1

CoreWCF.Primitives fixed: 1.9.1

Upgrade CoreWCF.Primitives to 1.9.1

Verify Direct and Transitive Dependencies

Run the following command in your project directory to verify that all resolved dependencies use the patched release:

inspect dependencies for CoreWCF.Primitives

How to Check if You Are Affected

To determine whether your application is affected by CVE-2026-54779, inspect your project dependencies for CoreWCF:

inspect dependencies for CoreWCF.Primitives

Analyze the terminal output to locate any version of CoreWCF in your dependency tree. If any resolved version matches the vulnerable ranges listed in the table below (for example, versions earlier than 1.8.1), your application is affected.

Note: Verify declared build manifests and deployed runtime container environments.

Technical Details

Vulnerability Mechanism & Technical Analysis

This vulnerability is classified under CWE-613: Insufficient Session Expiration, where according to wasc, "insufficient session expiration is when a web site permits an attacker to reuse old session credentials or session ids for authorization.". In CoreWCF, software state validation or input boundaries are circumvented during processing. Review the official source advisory statement below for specific affected components, classes, and reproduction details.

Source Advisory Statement

### Impact When enabling DetectReplayedTokens, a token can be replayed and will be detected despite it being reused. ### Patches Fixed in CoreWCF v1.8.1 and v1.9.1 ### Workarounds Provide your own implementation of `ITokenReplayCache` with the correct behavior.

CVE-2026-54779 Affected CoreWCF Versions

2 component(s)

Fixed Versions:

1.8.11.9.1

Product / Package	Ecosystem	Affected Versions	Fixed Version
CoreWCF.Primitives nuget/CoreWCF.Primitives	NuGet	< 1.8.1	1.8.1
CoreWCF.Primitives nuget/CoreWCF.Primitives	NuGet	≥ 1.9.0 < 1.9.1	1.9.1

References

GitHub Advisory / Wiki ADVISORY

https://github.com/CoreWCF/CoreWCF/security/advisories/GHSA-9jr3-rj99-8jq3

CoreWCF Source Repository REPOSITORY

https://github.com/CoreWCF/CoreWCF

Frequently Asked Questions

What is CVE-2026-54779?

CVE-2026-54779 is a security vulnerability in CoreWCF involving SAML token replay protection is inoperative under CWE-613: Insufficient Session Expiration.

Which CoreWCF versions are affected?

Affected versions include releases prior to 1.8.1, 1.9.1 across affected packages: CoreWCF.Primitives.

What version fixes CVE-2026-54779?

Upgrading to 1.8.1, 1.9.1 (or the latest patched release for your respective branch) resolves the vulnerability.

Is CoreWCF.Primitives affected?

Yes, CoreWCF.Primitives is affected in releases prior to 1.8.1, 1.9.1. Upgrade your dependency to 1.8.1, 1.9.1 or later.

What is the CVSS score of CVE-2026-54779?

CVE-2026-54779 has a CVSS v3.1 base score of 5.9 (MODERATE) with vector string CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:H/A:N.

What CWE is associated with CVE-2026-54779?

CVE-2026-54779 is classified under CWE-613: Insufficient Session Expiration (According to WASC, "Insufficient Session Expiration is when a web site permits an attacker to reuse old session credentials or session IDs for authorization.").

How can I check NuGet dependencies for CVE-2026-54779?

Run the dependency tree command: 'inspect dependencies for CoreWCF.Primitives'. This command lists direct and transitive dependencies in your build configuration so you can verify if a vulnerable version is resolved.

Machine-readable OSV JSON OSV v1.5 Schema

Normalized schema output

View Raw JSON

{
  "schema_version" : "1.4.0",
  "id" : "GHSA-9jr3-rj99-8jq3",
  "modified" : "2026-06-19T20:47:02Z",
  "published" : "2026-06-19T20:47:02Z",
  "aliases" : [ "CVE-2026-54779" ],
  "summary" : "CoreWCF: SAML token replay protection is inoperative",
  "details" : "### Impact\nWhen enabling DetectReplayedTokens, a token can be replayed and will be detected despite it being reused.\n\n### Patches\nFixed in CoreWCF v1.8.1 and v1.9.1\n\n### Workarounds\nProvide your own implementation of `ITokenReplayCache` with the correct behavior.",
  "severity" : [ {
    "type" : "CVSS_V3",
    "score" : "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:H/A:N"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "NuGet",
      "name" : "CoreWCF.Primitives"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "0"
      }, {
        "fixed" : "1.8.1"
      } ]
    } ]
  }, {
    "package" : {
      "ecosystem" : "NuGet",
      "name" : "CoreWCF.Primitives"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "1.9.0"
      }, {
        "fixed" : "1.9.1"
      } ]
    } ]
  } ],
  "references" : [ {
    "type" : "WEB",
    "url" : "https://github.com/CoreWCF/CoreWCF/security/advisories/GHSA-9jr3-rj99-8jq3"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/CoreWCF/CoreWCF"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-294", "CWE-613" ],
    "severity" : "MODERATE",
    "github_reviewed" : true,
    "github_reviewed_at" : "2026-06-19T20:47:02Z",
    "nvd_published_at" : null
  }
}

CVSS V3

5.9 MODERATE