CVE-2026-54777

MEDIUMPre-NVD 6.56.5
EchelonGraph scoreLOW confidence

This medium-severity CVE scores 6.5 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
6.5
EchelonGraph verdictMonitorLow exploitation likelihood right now — keep watching.
  • Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS: —CVSS: 6.5Exploit: NoneExposed: 0

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

CoreWCF NetNamedPipe transport accepts attach to a pre-existing named pipe instance

Impact

CoreWCF NetNamedPipe transport accepts attach to a pre-existing named pipe instance, allowing local interception of NetNamedPipe traffic. NetNamedPipe creates a shared memory object based on the listening url, then generated a unique GUID for the named pipe it will be using and saves this to the shared memory object. Then it creates the named pipe to listen for clients. This requires an attacker to race the service and create the named pipe between the service publishing the GUID to the shared memory location (which the attacker needs to read) and the service creating the named pipe itself.

Patches

Fixed in CoreWCF v1.8.1 and v1.9.1

Workarounds

None

CVSS v3
6.5
EG Score
6.5(low)
EPSS
—
KEV
Not listed

Published

June 19, 2026

Last Modified

June 19, 2026

Vendor Advisories for CVE-2026-54777(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.NetNamedPipe1.9.01.9.1—

Data Freshness Timeline

(refreshed 6× in last 7d / 17× 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 09:31 UTCEG score recompute
  2. 2026-07-05 08:32 UTCEG score recompute
  3. 2026-07-04 07:49 UTCEG score recompute
  4. 2026-07-03 07:06 UTCEG score recompute
  5. 2026-07-02 06:24 UTCEG score recompute
  6. 2026-07-01 05:43 UTCEG score recompute
  7. 2026-06-30 04:57 UTCEG score recompute
  8. 2026-06-29 04:01 UTCEG score recompute
  9. 2026-06-28 03:06 UTCEG score recompute
  10. 2026-06-27 02:25 UTCEG score recompute
  11. 2026-06-26 01:43 UTCEG score recompute
  12. 2026-06-25 01:02 UTCEG score recompute
  13. 2026-06-24 00:20 UTCEG score recompute
  14. 2026-06-22 23:37 UTCEG score recompute
  15. 2026-06-21 22:56 UTCEG score recompute
  16. 2026-06-20 22:09 UTCEG score recompute
  17. 2026-06-19 21:25 UTCEG score recompute

Frequently asked(4)

What is CVE-2026-54777?
CVE-2026-54777 is a medium vulnerability published on June 19, 2026. CoreWCF NetNamedPipe transport accepts attach to a pre-existing named pipe instance Impact CoreWCF NetNamedPipe transport accepts attach to a pre-existing named pipe instance, allowing local interception of NetNamedPipe traffic. NetNamedPipe creates a shared memory object based on the listening…
When was CVE-2026-54777 disclosed?
CVE-2026-54777 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-2026-54777?
CVE-2026-54777 has a CVSS v4.0 base score of 6.5 (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-2026-54777?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-54777, 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-2026-54777

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