Vulnerability · Published Jul 8, 2026 · Assigned by GitHub_M

CVE-2026-54779CoreWCF: SAML token replay protection is inoperative

Medium 5.9

In plain English

A medium-severity security flaw in CoreWCF from CoreWCF. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.4% (higher than 38% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.

Severity (CVSS 3.1)5.9Medium

Exploit odds (30 days)0.4%top 62.1% of all CVEs

Exploited in the wildNo reportsCISA SSVC: none

Attack toolingNoneno public tooling known

Official description

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.

Affected packages & fixed versions

Ecosystem	Package	Fixed in	Advisory
NuGet	corewcf.primitives	1.8.1	GHSA-9jr3-rj99-8jq3
NuGet	corewcf.primitives	1.9.1	GHSA-9jr3-rj99-8jq3

Affected products (as reported)

Vendor	Product	Versions
CoreWCF	CoreWCF	>= 1.9.0, < 1.9.1< 1.8.1

Weakness: CWE-294, CWE-613 · Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:H/A:N

References

https://github.com/CoreWCF/CoreWCF/security/advisories/GHSA-9jr3-rj99-8jq3 x_refsource_CONFIRM
https://github.com/CoreWCF/CoreWCF/commit/3800c4e2bb4c6fde00ddacefdc2221ef33d55621 x_refsource_MISC
https://github.com/CoreWCF/CoreWCF/commit/7b0b5231cf21b4b5c1fc3caac9981f8bee43823f x_refsource_MISC
https://github.com/CoreWCF/CoreWCF/commit/84f8cff5a786b5aaa73448cb379d366a7df98238 x_refsource_MISC
https://github.com/CoreWCF/CoreWCF/releases/tag/v1.8.1 x_refsource_MISC
https://github.com/CoreWCF/CoreWCF/releases/tag/v1.9.1 x_refsource_MISC