CVE-2026-54783: CoreWCF XML Signature Wrapping Vulnerability

HIGH
Advisory Identifier: GHSA-gqv6-pwcg-87r8
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CVSS 7.4
CWE-294 CWE-345 CWE-347
Published
Advisory Summary

CVE-2026-54783 is a HIGH (CVSS 7.4) xml signature wrapping vulnerability (CWE-294: Authentication Bypass by Capture-replay) affecting CoreWCF libraries in the NuGet ecosystem. The issue involves xml signature wrapping in ws-security endorsing/supporting signature verification allows replay of captured signed messages. Remediation is available by upgrading affected packages to version 1.8.1, 1.9.1.

CVE-2026-54783 at a Glance

CVE Identifier CVE-2026-54783
GHSA Identifier GHSA-gqv6-pwcg-87r8
Severity HIGH
CVSS v3.1 Base Score 7.4
CWE Classification CWE-294: Authentication Bypass by Capture-replay
Affected Product CoreWCF
Package Ecosystem NuGet
Published Date
Last Updated

Security Impact

CVSS: 7.4

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:H/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 High (C:H)
Integrity High (I:H)
Availability None (A:N)

How to Fix CVE-2026-54783

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-2026-54783, 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-294: Authentication Bypass by Capture-replay, where a capture-replay flaw exists when the design of the product makes it possible for a malicious user to sniff network traffic and bypass authentication by replaying it to the server in question to the same effect as the original message (or with minor changes). 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 The attacker, with one captured signed SOAP envelope from a victim and no other privileges, can invoke arbitrary operations on the service as the victim principal for the lifetime of the captured signing key. There is no rate limit on replays. The DetectReplays setting on transport-security bindings does not mitigate the issue because the attack does not reuse the original timestamp — the fresh timestamp in the wsse:Security header is what the replay-detection logic inspects. ### Patches Fixed in CoreWCF v1.8.1 and v1.9.1 ### Workarounds Ensure communication is protected by SSL/TLS to prevent capturing of signed SOAP envelope.

CVE-2026-54783 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-gqv6-pwcg-87r8
CoreWCF Source Repository REPOSITORY
https://github.com/CoreWCF/CoreWCF

Frequently Asked Questions

What is CVE-2026-54783?
CVE-2026-54783 is a security vulnerability in CoreWCF involving XML Signature Wrapping in WS-Security endorsing/supporting signature verification allows replay of captured signed messages under CWE-294: Authentication Bypass by Capture-replay.
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-2026-54783?
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-2026-54783?
CVE-2026-54783 has a CVSS v3.1 base score of 7.4 (HIGH) with vector string CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N.
What CWE is associated with CVE-2026-54783?
CVE-2026-54783 is classified under CWE-294: Authentication Bypass by Capture-replay (A capture-replay flaw exists when the design of the product makes it possible for a malicious user to sniff network traffic and bypass authentication by replaying it to the server in question to the same effect as the original message (or with minor changes).).
How can I check NuGet dependencies for CVE-2026-54783?
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-gqv6-pwcg-87r8",
  "modified" : "2026-06-19T20:47:14Z",
  "published" : "2026-06-19T20:47:14Z",
  "aliases" : [ "CVE-2026-54783" ],
  "summary" : "CoreWCF: XML Signature Wrapping in WS-Security endorsing/supporting signature verification allows replay of captured signed messages",
  "details" : "### Impact\nThe attacker, with one captured signed SOAP envelope from a victim and no other privileges, can invoke arbitrary operations on the service as the victim principal for the lifetime of the captured signing key. There is no rate limit on replays. The DetectReplays setting on transport-security bindings does not mitigate the issue because the attack does not reuse the original timestamp — the fresh timestamp in the wsse:Security header is what the replay-detection logic inspects.\n\n### Patches\nFixed in CoreWCF v1.8.1 and v1.9.1\n\n### Workarounds\nEnsure communication is protected by SSL/TLS to prevent capturing of signed SOAP envelope.",
  "severity" : [ {
    "type" : "CVSS_V3",
    "score" : "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/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-gqv6-pwcg-87r8"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/CoreWCF/CoreWCF"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-294", "CWE-345", "CWE-347" ],
    "severity" : "HIGH",
    "github_reviewed" : true,
    "github_reviewed_at" : "2026-06-19T20:47:14Z",
    "nvd_published_at" : null
  }
}