GHSA-WJPQ-6766-7F5J

Vulnerability from github – Published: 2026-06-19 20:46 – Updated: 2026-06-19 20:46
VLAI
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
Show details on source website
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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"
}



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