Vulnerability in Corewcf

CVE-2026-54778

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.

Vulnerability class: Race Condition

Published · last modified .

CVSS v3 metric

CVSS v3 base score 6.2 (Medium). Vector: CVSS:3.1/AV:L/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:H.

EPSS exploit prediction

EPSS: 0.001 (2.1th percentile), scored .

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 2nd percentile — 2.1% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS trend (30 days)EPSS over the last 30 days for CVE-2026-54778: held from 0.001 to 0.001.

EPSS over last 30 days · oldest: 0.001 · newest: 0.001 · change: 0.000

Affected products

  • Corewcf — versions >= 1.9.0, < 1.9.1, < 1.8.1

Weakness classification (CWE)

References

Frequently asked questions

What is CVE-2026-54778?
CVE-2026-54778 is a medium-severity vulnerability in Corewcf, classified under Concurrent Execution using Shared Resource with Improper Synchronization (Race Condition). CVSS score: 6.2/10. Published 2026-07-08.
How severe is CVE-2026-54778?
Medium severity. CVSS v3 base score is 6.2 out of 10.