Answer in brief
CVE-2026-54779 records a Medium severity (CVSS 5.9) vulnerability in CoreWCF: SAML token replay protection is inoperative. The current sources do not mark it as known exploited. The current feed maps CoreWCF/CoreWCF (generic), CoreWCF.Primitives (nuget), CoreWCF.Primitives (nuget). Check affected ranges and fixed versions before updating.
Analysis pending evidence review
HOL Guard separates source facts from reviewed analysis. See the methodology.
CVSS is 5.9. The current sources do not mark it as known exploited. Treat this as a source-backed prioritization signal, not a statement about your environment.
Analysis status
Analysis pending evidence review
Factual feed record only; HOL analysis is not approved for indexing. Read the methodology.
The current feed maps CoreWCF/CoreWCF (generic), CoreWCF.Primitives (nuget), CoreWCF.Primitives (nuget). Check affected ranges and fixed versions before updating.
| Package | Affected range | Fixed version |
|---|---|---|
| CoreWCF/CoreWCFgeneric | >= 1.9.0, < 1.9.1 || < 1.8.1 | Not reported |
| CoreWCF.Primitivesnuget | <1.8.1 | 1.8.1 |
| CoreWCF.Primitivesnuget | >=1.9.0,<1.9.1 | 1.9.1 |
Published upstream
Jul 8, 2026
Evidence: source:cvelist:source_dates:source-dates:recordSource modified
Jul 9, 2026
Evidence: source:cvelist:source_dates:source-dates:recordFirst seen by HOL
Jun 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 SAML token replay protection is inoperative because DefaultTokenReplayCache.TryAdd does not reject duplicate tokens when DetectReplayedTokens is enabled, allowing a captured token to be reused. This issue is fixed in versions 1.8.1 and 1.9.1.
Quoted source text, attributed separately from HOL analysis.