Vulnerability-Lookup

GHSA-WJPQ-6766-7F5J

Vulnerability from github – Published: 2026-06-19 20:46 – Updated: 2026-06-19 20:46

Summary

CoreWCF: Unix Domain Socket PosixIdentity transport accepts connections that skip the security upgrade

Details

Impact

A CoreWCF service hosted on Unix Domain Sockets with the PosixIdentity client credential type (UnixDomainSocketBinding with Security.Mode = TransportCredentialOnly and Security.Transport.ClientCredentialType = PosixIdentity) does not require the client to perform the application/unixposix stream upgrade before dispatching messages.

Patches

Fixed in CoreWCF v1.8.1 and v1.9.1

Workarounds

Restrict filesystem access to the UDS socket file using owner/group/mode (e.g. chmod 0660 plus a dedicated group) so that only the POSIX users who are already authorized to invoke the service can connect at all. This makes the missing-upgrade behaviour equivalent to the operating system’s filesystem permissions instead of relying on framing-layer identity checks. Avoid relying on ServiceSecurityContext.PrimaryIdentity for authorization decisions, or back it up with an authentication-required authorization policy that rejects anonymous principals.

Severity

4.4 (Medium)


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

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JSON

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{
  "affected": [
    {
      "package": {
        "ecosystem": "NuGet",
        "name": "CoreWCF.UnixDomainSocket"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "1.8.1"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    },
    {
      "package": {
        "ecosystem": "NuGet",
        "name": "CoreWCF.UnixDomainSocket"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "1.9.0"
            },
            {
              "fixed": "1.9.1"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "aliases": [
    "CVE-2026-54776"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-306"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2026-06-19T20:46:52Z",
    "nvd_published_at": null,
    "severity": "MODERATE"
  },
  "details": "### Impact\nA CoreWCF service hosted on Unix Domain Sockets with the PosixIdentity client credential type (UnixDomainSocketBinding with Security.Mode = TransportCredentialOnly and Security.Transport.ClientCredentialType = PosixIdentity) does not require the client to perform the application/unixposix stream upgrade before dispatching messages.\n\n### Patches\nFixed in CoreWCF v1.8.1 and v1.9.1\n\n### Workarounds\nRestrict filesystem access to the UDS socket file using owner/group/mode (e.g. chmod 0660 plus a dedicated group) so that only the POSIX users who are already authorized to invoke the service can connect at all. This makes the missing-upgrade behaviour equivalent to the operating system\u2019s filesystem permissions instead of relying on framing-layer identity checks.\nAvoid relying on ServiceSecurityContext.PrimaryIdentity for authorization decisions, or back it up with an authentication-required authorization policy that rejects anonymous principals.",
  "id": "GHSA-wjpq-6766-7f5j",
  "modified": "2026-06-19T20:46:52Z",
  "published": "2026-06-19T20:46:52Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/CoreWCF/CoreWCF/security/advisories/GHSA-wjpq-6766-7f5j"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/CoreWCF/CoreWCF"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:N",
      "type": "CVSS_V3"
    }
  ],
  "summary": "CoreWCF: Unix Domain Socket PosixIdentity transport accepts connections that skip the security upgrade"
}

CVE-2026-54776 (GCVE-0-2026-54776)

Vulnerability from cvelistv5 – Published: 2026-07-08 22:04 – Updated: 2026-07-09 12:56

Title

CoreWCF: Unix Domain Socket PosixIdentity transport accepts connections that skip the security upgrade

Summary

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, a CoreWCF service hosted on Unix Domain Sockets with PosixIdentity client credentials can accept connections that skip the application/unixposix stream upgrade before dispatching messages, bypassing framing-layer identity checks in UnixPosixIdentitySecurityUpgradeProvider. This issue is fixed in versions 1.8.1 and 1.9.1.

Severity

4.4 (Medium)


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

SSVC

Exploitation: none Automatable: no Technical Impact: partial

CISA Coordinator · CISA-ADP (v2.0.3)

Decision recorded 2026-07-09 12:56 UTC

CWE

CWE-306 - Missing Authentication for Critical Function

Assigner

GitHub_M mitre root Scorecard

References

6 references

URL	Tags
https://github.com/CoreWCF/CoreWCF/security/advis…	x_refsource_CONFIRM
https://github.com/CoreWCF/CoreWCF/commit/9944312…	x_refsource_MISC
https://github.com/CoreWCF/CoreWCF/commit/9af1695…	x_refsource_MISC
https://github.com/CoreWCF/CoreWCF/commit/f2f1a05…	x_refsource_MISC
https://github.com/CoreWCF/CoreWCF/releases/tag/v1.8.1	x_refsource_MISC
https://github.com/CoreWCF/CoreWCF/releases/tag/v1.9.1	x_refsource_MISC

Impacted products

1 product

Vendor	Product	Version
CoreWCF	CoreWCF	Affected: >= 1.9.0, < 1.9.1 Affected: < 1.8.1

Show details on NVD website

JSON

To clipboard

{
  "containers": {
    "adp": [
      {
        "metrics": [
          {
            "other": {
              "content": {
                "id": "CVE-2026-54776",
                "options": [
                  {
                    "Exploitation": "none"
                  },
                  {
                    "Automatable": "no"
                  },
                  {
                    "Technical Impact": "partial"
                  }
                ],
                "role": "CISA Coordinator",
                "timestamp": "2026-07-09T12:56:10.364263Z",
                "version": "2.0.3"
              },
              "type": "ssvc"
            }
          }
        ],
        "providerMetadata": {
          "dateUpdated": "2026-07-09T12:56:16.584Z",
          "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
          "shortName": "CISA-ADP"
        },
        "title": "CISA ADP Vulnrichment"
      }
    ],
    "cna": {
      "affected": [
        {
          "product": "CoreWCF",
          "vendor": "CoreWCF",
          "versions": [
            {
              "status": "affected",
              "version": "\u003e= 1.9.0, \u003c 1.9.1"
            },
            {
              "status": "affected",
              "version": "\u003c 1.8.1"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "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, a CoreWCF service hosted on Unix Domain Sockets with PosixIdentity client credentials can accept connections that skip the application/unixposix stream upgrade before dispatching messages, bypassing framing-layer identity checks in UnixPosixIdentitySecurityUpgradeProvider. This issue is fixed in versions 1.8.1 and 1.9.1."
        }
      ],
      "metrics": [
        {
          "cvssV3_1": {
            "attackComplexity": "LOW",
            "attackVector": "LOCAL",
            "availabilityImpact": "NONE",
            "baseScore": 4.4,
            "baseSeverity": "MEDIUM",
            "confidentialityImpact": "LOW",
            "integrityImpact": "LOW",
            "privilegesRequired": "LOW",
            "scope": "UNCHANGED",
            "userInteraction": "NONE",
            "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:N",
            "version": "3.1"
          }
        }
      ],
      "problemTypes": [
        {
          "descriptions": [
            {
              "cweId": "CWE-306",
              "description": "CWE-306: Missing Authentication for Critical Function",
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              "type": "CWE"
            }
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      ],
      "providerMetadata": {
        "dateUpdated": "2026-07-08T22:04:39.200Z",
        "orgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
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      },
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          "name": "https://github.com/CoreWCF/CoreWCF/security/advisories/GHSA-wjpq-6766-7f5j",
          "tags": [
            "x_refsource_CONFIRM"
          ],
          "url": "https://github.com/CoreWCF/CoreWCF/security/advisories/GHSA-wjpq-6766-7f5j"
        },
        {
          "name": "https://github.com/CoreWCF/CoreWCF/commit/994431268e3362c0cd126450fe2a135c202551f3",
          "tags": [
            "x_refsource_MISC"
          ],
          "url": "https://github.com/CoreWCF/CoreWCF/commit/994431268e3362c0cd126450fe2a135c202551f3"
        },
        {
          "name": "https://github.com/CoreWCF/CoreWCF/commit/9af16955e51a57348dafce0019e259a092ef7440",
          "tags": [
            "x_refsource_MISC"
          ],
          "url": "https://github.com/CoreWCF/CoreWCF/commit/9af16955e51a57348dafce0019e259a092ef7440"
        },
        {
          "name": "https://github.com/CoreWCF/CoreWCF/commit/f2f1a05927a88b8a75fa0582fa8ed75eb891e463",
          "tags": [
            "x_refsource_MISC"
          ],
          "url": "https://github.com/CoreWCF/CoreWCF/commit/f2f1a05927a88b8a75fa0582fa8ed75eb891e463"
        },
        {
          "name": "https://github.com/CoreWCF/CoreWCF/releases/tag/v1.8.1",
          "tags": [
            "x_refsource_MISC"
          ],
          "url": "https://github.com/CoreWCF/CoreWCF/releases/tag/v1.8.1"
        },
        {
          "name": "https://github.com/CoreWCF/CoreWCF/releases/tag/v1.9.1",
          "tags": [
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          "url": "https://github.com/CoreWCF/CoreWCF/releases/tag/v1.9.1"
        }
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      "source": {
        "advisory": "GHSA-wjpq-6766-7f5j",
        "discovery": "UNKNOWN"
      },
      "title": "CoreWCF: Unix Domain Socket PosixIdentity transport accepts connections that skip the security upgrade"
    }
  },
  "cveMetadata": {
    "assignerOrgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
    "assignerShortName": "GitHub_M",
    "cveId": "CVE-2026-54776",
    "datePublished": "2026-07-08T22:04:39.200Z",
    "dateReserved": "2026-06-15T23:23:57.713Z",
    "dateUpdated": "2026-07-09T12:56:16.584Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}

Sightings

Author	Source	Type	Date	Other

Nomenclature

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Confirmed: The vulnerability has been validated from an analyst's perspective.
Published Proof of Concept: A public proof of concept is available for this vulnerability.
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Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
Not confirmed: The user expressed doubt about the validity of the vulnerability.
Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.

The MITRE ATT&CK techniques below are AI-generated suggestions, inferred from the description of the vulnerability by the CIRCL/vulnerability-attack-technique-classification-roberta-base model, served locally by ML-Gateway. They have not been verified by an analyst and are provided for guidance only.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.
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