CVE-2026-54778

MEDIUMPre-NVD 6.26.2—
EchelonGraph scoreMEDIUM confidence

This medium-severity CVE scores 6.2 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
6.2
EchelonGraph verdictMonitorLow exploitation likelihood right now — keep watching.
  • Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS: 0%CVSS: 6.2Exploit: NoneExposed: 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, CoreWCF UnixDomainSocket POSIX peer identity resolution uses non-reentrant getpwuid and getgrgid calls, allowing concurrent connections to attribute one connection's identity to another or crash the host process under contention. This issue is fixed in versions 1.8.1 and 1.9.1.

CVSS v3
6.2
EG Score
6.2(medium)
EPSS
1.0%
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 b4867547c94b (CoreWCF/CoreWCF)

Patch available: CoreWCF/CoreWCF v1.9.1 (contains commit b4867547c94b)

https://github.com/CoreWCF/CoreWCF/commit/b4867547c94bb088568935d581a55dda18a621e1
github_commit Patch Available

commit b0acb105589b (CoreWCF/CoreWCF)

Patch available: CoreWCF/CoreWCF v1.8.1 (contains commit b0acb105589b)

https://github.com/CoreWCF/CoreWCF/commit/b0acb105589b455a095ea5ff49f5191e4eeff791
github_commit

commit a3d95ea4627b (CoreWCF/CoreWCF)

Fix landed in CoreWCF/CoreWCF commit a3d95ea4627b — awaiting tagged release

https://github.com/CoreWCF/CoreWCF/commit/a3d95ea4627b818995e92c7def4c016164cacfce
github Patch Available

UnixDomainSocket Non-Reentrant POSIX Identity Resolution · Advisory · CoreWCF/CoreWCF · GitHub

https://github.com/CoreWCF/CoreWCF/security/advisories/GHSA-q6v9-43v5-jv9q

Vendor Advisories for CVE-2026-54778(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(2)

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

Data Freshness Timeline

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

Related CVEs(same CWE)

Frequently asked(5)

What is CVE-2026-54778?
CVE-2026-54778 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, CoreWCF UnixDomainSocket POSIX peer identity resolution uses non-reentrant getpwuid and getgrgid calls, allowing concurrent connections to attribute one connection's identity to…
When was CVE-2026-54778 disclosed?
CVE-2026-54778 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-2026-54778 actively exploited?
CVE-2026-54778 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 1.0% percentile likelihood of exploitation in the next 30 days — higher percentiles indicate greater predicted risk.
What is the CVSS score of CVE-2026-54778?
CVE-2026-54778 has a CVSS v3 base score of 6.2 (NVD).
How do I remediate CVE-2026-54778?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-54778, 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

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