CVE-2026-54778
CoreWCF: UnixDomainSocket Non-Reentrant POSIX Identity Resolution
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.
Attack profile
How easy it is to exploit
- Attack vector
- Local
- Complexity
- High
- Privileges needed
- None
- User interaction
- None
What an attacker can affect
- Confidentiality
- Low
- Integrity
- Low
- Availability
- High
Exploit likelihood
What each source reports
CVE List Score used
CoreWCF: UnixDomainSocket Non-Reentrant POSIX Identity Resolution
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.
- Record
CVE-2026-54778- CVSS 3.1
- 6.2 Medium
CVSS:3.1/AV:L/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:H - Weakness
- CWE-362, CWE-825
- Updated
- 2026-11-02
EUVDEUVD-2026-42465
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.
- Record
EUVD-2026-42465- CVSS 3.1
- 6.2 Medium
CVSS:3.1/AV:L/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:H - Updated
- 2026-11-02
GitHub AdvisoriesGHSA-q6v9-43v5-jv9q
CoreWCF: UnixDomainSocket Non-Reentrant POSIX Identity Resolution
Impact
Race condition in POSIX peer identity resolution may attribute one connection’s identity to another (getpwuid/getgrgid non-reentrant) and may crash the host process under contention.
Patches
Fixed in CoreWCF v1.8.1 and v1.9.1
Workarounds
Restrict UDS filesystem permissions so that only trusted local users can connect to the socket path. The race still exists but the attacker pool is constrained.
- Record
GHSA-q6v9-43v5-jv9q- CVSS 3.1
- 6.2 Medium
CVSS:3.1/AV:L/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:H - Weakness
- CWE-362, CWE-825
- Updated
- 2026-11-02
NVD
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.
- Record
CVE-2026-54778- CVSS 3.1
- 6.2 Medium
CVSS:3.1/AV:L/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:H - Weakness
- CWE-362, CWE-825
- Updated
- 2026-11-02
OSV
CoreWCF: UnixDomainSocket Non-Reentrant POSIX Identity Resolution
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.
- Record
CVE-2026-54778- CVSS 3.1
- 6.2 Medium
CVSS:3.1/AV:L/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:H - Weakness
- CWE-362, CWE-825
- Updated
- 2026-11-02
OSVGHSA-q6v9-43v5-jv9q
CoreWCF: UnixDomainSocket Non-Reentrant POSIX Identity Resolution
Impact
Race condition in POSIX peer identity resolution may attribute one connection’s identity to another (getpwuid/getgrgid non-reentrant) and may crash the host process under contention.
Patches
Fixed in CoreWCF v1.8.1 and v1.9.1
Workarounds
Restrict UDS filesystem permissions so that only trusted local users can connect to the socket path. The race still exists but the attacker pool is constrained.
- Record
GHSA-q6v9-43v5-jv9q- CVSS 3.1
- 6.2 Medium
CVSS:3.1/AV:L/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:H - Weakness
- CWE-362, CWE-825
- Updated
- 2026-11-02
Affected products
Affected packages
| Package | Affected | Fixed |
|---|---|---|
CoreWCF.UnixDomainSocketNuGet |
before 1.8.1 | 1.8.1 |
CoreWCF.UnixDomainSocketNuGet |
1.9.0 up to 1.9.1 | 1.9.1 |
CoreWCF.UnixDomainSocketNuGet |
before 1.8.1, plus listed versions 1.5.01.5.0-preview11.5.11.5.21.6.01.7.01.8.0 |
1.8.1 |
History
| Recorded | Changed | Sources |
|---|---|---|
| first indexed | CVE List, EUVD, GitHub Advisories, NVD, OSV |
Dates are when Every CVE recorded each change. Upstream dates may differ.
In short
CVE-2026-54778 is a medium vulnerability (CVSS 6.2) in Corewcf, published June 19, 2026. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 0.13%, the 2nd percentile. Fixed in CoreWCF.UnixDomainSocket 1.8.1.
References
github.com/CoreWCF/CoreWCF/security/advisories/GHSA-q6v9-43v5-jv9q