CVE-2026-54776

MEDIUMPre-NVD 4.44.4
EchelonGraph scoreLOW confidence

This medium-severity CVE scores 4.4 under the CNA's CVSS (NVD's own analysis pending). EPSS exploit-prediction score not yet available (the EPSS model rescores nightly; freshly-published CVEs typically appear within 48 hours). GitHub Security Advisory data not yet ingested — confidence will rise once GHSA publishes (typical lag: hours to days for open-source ecosystem CVEs; never for infrastructure-only CVEs).

Triggered by: NVD CVSS baseline
Sources: cna:github_m
4.4
EchelonGraph verdictMonitorLow exploitation likelihood right now — keep watching.
  • Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS: —CVSS: 4.4Exploit: NoneExposed: 0

No vendor fix yet — apply a workaround or compensating control (WAF / firewall / segmentation) and watch for a patch.

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

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.

CVSS v3
4.4
EG Score
4.4(low)
EPSS
—
KEV
Not listed

Published

June 19, 2026

Last Modified

June 19, 2026

Vendor Advisories for CVE-2026-54776(1)

These vendors published their own advisory mentioning this CVE — often with vendor-specific remediation steps + affected product lists not in NVD.

Affected Packages

(1 across 1 ecosystem)
NuGet(1)
PackageVulnerable rangeFixed inDependents
CoreWCF.UnixDomainSocket1.9.01.9.1—

Data Freshness Timeline

(refreshed 7× in last 7d / 18× in last 30d)

Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. Most recent first.

  1. 2026-07-06 23:38 UTCEG score recompute
  2. 2026-07-05 23:29 UTCEG score recompute
  3. 2026-07-04 23:23 UTCEG score recompute
  4. 2026-07-03 23:15 UTCEG score recompute
  5. 2026-07-02 22:57 UTCEG score recompute
  6. 2026-07-01 22:50 UTCEG score recompute
  7. 2026-06-30 22:44 UTCEG score recompute
  8. 2026-06-29 22:38 UTCEG score recompute
  9. 2026-06-28 22:32 UTCEG score recompute
  10. 2026-06-27 22:25 UTCEG score recompute
  11. 2026-06-26 22:19 UTCEG score recompute
  12. 2026-06-25 22:13 UTCEG score recompute
  13. 2026-06-24 22:05 UTCEG score recompute
  14. 2026-06-23 21:56 UTCEG score recompute
  15. 2026-06-22 21:45 UTCEG score recompute
  16. 2026-06-21 21:40 UTCEG score recompute
  17. 2026-06-20 21:32 UTCEG score recompute
  18. 2026-06-19 21:25 UTCEG score recompute

Frequently asked(4)

What is CVE-2026-54776?
CVE-2026-54776 is a medium vulnerability published on June 19, 2026. CoreWCF: Unix Domain Socket PosixIdentity transport accepts connections that skip the security upgrade Impact A CoreWCF service hosted on Unix Domain Sockets with the PosixIdentity client credential type (UnixDomainSocketBinding with Security.Mode = TransportCredentialOnly and…
When was CVE-2026-54776 disclosed?
CVE-2026-54776 was first published in the National Vulnerability Database on June 19, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
What is the CVSS score of CVE-2026-54776?
CVE-2026-54776 has a CVSS v4.0 base score of 4.4 (CNA self-assessment; NVD's own analysis pending). The EG score is currently aggregating — additional source signals are being incorporated as they become available..
How do I remediate CVE-2026-54776?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-54776, EchelonGraph cross-links them in the Vendor Advisories panel below — those typically contain the canonical remediation steps, fixed version numbers, and any vendor-specific mitigations.

Dependency Blast Radius

See which npm, PyPI, Go, and Maven packages are affected by CVE-2026-54776

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