CVE-2026-54776

MEDIUMPre-NVD 4.44.4—
EchelonGraph scoreMEDIUM confidence

This medium-severity CVE scores 4.4 under a secondary CVSS source (NVD's own analysis pending). EPSS exploit probability: 0.1%, top 99% of all CVEs by exploit prediction. 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: epss, secondary
4.4EG
EchelonGraph verdictMonitorLow exploitation likelihood right now — keep watching.
  • Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS PROB: 0%CVSS: 4.4Exploit: None knownExposed: 0

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

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.

CVSS v3
4.4
EG Score
4.4(medium)
EG Risk
20(Track)
EG Risk 20/100SSVC: Track

EG Risk is EchelonGraph's 0–100 priority score: it fuses intrinsic severity with real-world exploitation and automatability so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner. Distinct from the 0–10 EG Score (severity).

How it’s computed
Severity44% × 45%
Exploitation0% × 40%
Automatability0% × 15%
Action: Routine — remediate on your standard cadence.
EPSS PROB
0%
EPSS %ILE
1%
KEV
Not listed

Published

June 19, 2026

Last Modified

July 9, 2026

Advisory Details (6)

Auto-updated Jul 8, 2026
Patch available. Sources: github, github_commit, github_release.
github_release Patch Available

CoreWCF v1.9.1

Patch available: CoreWCF/CoreWCF v1.9.1

https://github.com/CoreWCF/CoreWCF/releases/tag/v1.9.1
github_release Patch Available

CoreWCF v1.8.1

Patch available: CoreWCF/CoreWCF v1.8.1

https://github.com/CoreWCF/CoreWCF/releases/tag/v1.8.1
github_commit Patch Available

commit f2f1a05927a8 (CoreWCF/CoreWCF)

Patch available: CoreWCF/CoreWCF v1.9.1 (contains commit f2f1a05927a8)

https://github.com/CoreWCF/CoreWCF/commit/f2f1a05927a88b8a75fa0582fa8ed75eb891e463
github_commit Patch Available

commit 9af16955e51a (CoreWCF/CoreWCF)

Patch available: CoreWCF/CoreWCF v1.8.1 (contains commit 9af16955e51a)

https://github.com/CoreWCF/CoreWCF/commit/9af16955e51a57348dafce0019e259a092ef7440
github_commit

commit 994431268e33 (CoreWCF/CoreWCF)

Fix landed in CoreWCF/CoreWCF commit 994431268e33 — awaiting tagged release

https://github.com/CoreWCF/CoreWCF/commit/994431268e3362c0cd126450fe2a135c202551f3
github Patch Available

Unix Domain Socket PosixIdentity transport accepts connections that skip the security upgrade · Advisory · CoreWCF/CoreWCF · GitHub

https://github.com/CoreWCF/CoreWCF/security/advisories/GHSA-wjpq-6766-7f5j

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—

Weakness Classification(1)

MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.

Data Freshness Timeline

(refreshed 7× in last 7d / 21× 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. 2026-07-26 16:48 UTCEG score recompute
  2. 2026-07-26 14:54 UTCEPSS rescore
  3. 2026-07-24 14:18 UTCEPSS rescore
  4. 2026-07-23 14:18 UTCEPSS rescore
  5. 2026-07-23 03:19 UTCEG score recompute
  6. 2026-07-22 14:08 UTCEPSS rescore
  7. 2026-07-20 17:08 UTCEPSS rescore
  8. 2026-07-19 14:31 UTCEPSS rescore
  9. 2026-07-19 14:31 UTCEPSS rescore
  10. 2026-07-18 10:04 UTCEPSS rescore
  11. 2026-07-16 17:03 UTCEPSS rescore
  12. 2026-07-15 16:57 UTCEPSS rescore
  13. 2026-07-15 16:57 UTCEPSS rescore
  14. 2026-07-15 02:00 UTCEPSS rescore
  15. 2026-07-15 02:00 UTCEPSS rescore
  16. 2026-07-13 22:31 UTCEPSS rescore
  17. 2026-07-12 05:46 UTCEPSS rescore
  18. 2026-07-11 08:27 UTCEPSS rescore
  19. 2026-07-11 08:27 UTCEPSS rescore
  20. 2026-07-09 19:10 UTCEPSS rescore
  21. 2026-07-09 19:10 UTCEPSS rescore
  22. 2026-06-19 21:25 UTCEG score recompute

Frequently asked(5)

What is CVE-2026-54776?
CVE-2026-54776 is a medium vulnerability published on June 19, 2026. 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…
When was CVE-2026-54776 disclosed?
CVE-2026-54776 was first published in the National Vulnerability Database on June 19, 2026, with the most recent update on July 9, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-54776 actively exploited?
CVE-2026-54776 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0% probability of exploitation in the next 30 days, which ranks it in the top 98.5% of all scored CVEs.
What is the CVSS score of CVE-2026-54776?
CVE-2026-54776 has a CVSS v3 base score of 4.4 (NVD).
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

Explore →

Is Your Infrastructure Affected by CVE-2026-54776?

EchelonGraph automatically scans your cloud infrastructure and maps CVE exposure using blast radius analysis.

Start Free Scan →Browse All CVEs