GHSA-48pq-2xq3-c2m4
HIGHGHSA-48pq-2xq3-c2m4 is a high-severity (CVSS 7.4) Improper Authentication vulnerability in CoreWCF.Primitives. O3 Security confirms whether GHSA-48pq-2xq3-c2m4 is actually reachable in your code before you act, and blocks exploitation at runtime until you patch.
CoreWCF: SAML SubjectConfirmation methods and holder-of-key proof keys are not enforced
Exploitation Status
No confirmed exploitation observed yet
- A successful exploit gives an attacker total control of the affected component, not partial access.
- CISA’s own triage has not observed active exploitation or public proof-of-concept code for this CVE as of its last assessment.
Exploitation and automatability from CISA’s SSVC triage for GHSA-48pq-2xq3-c2m4.
EPSS Exploitation Probability
EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.
How urgent is this, really
GHSA-48pq-2xq3-c2m4 plotted by exploitation likelihood (EPSS) against impact (CVSS). The shaded corner — EPSS 50%+ and CVSS 7.0+ — is where this CVE doesn't sit, though severity or exploitability alone can still warrant action.
Where this sits among everything scored
Of 363,588 CVEs with a current EPSS score, this one falls in the < 10% band (highlighted). Real counts from FIRST.org, not a sample — log-scaled since the landscape is heavily right-skewed.
Real-World Exposure
CoreWCF.Primitives.NETCoreWCF.PrimitivesReal-time download stats are indexed for npm and PyPI packages. This vulnerability affects NuGet packages — download data is not available via public APIs for these ecosystems.
Description
Impact
The relying application is given a ClaimsPrincipal for a subject whose authority over the assertion the sender never proved. There are two distinct exploit shapes:
- Holder-of-key downgrade. An attacker who obtains a holder-of-key SAML assertion that was issued without KeyInfo (issuer bug, custom STS shape, or assertion captured from an interaction where KeyInfo was elided) can present it to the service and be authenticated as the assertion’s subject without producing the proof key the assertion’s confirmation method would normally require. The service’s reliance on holder-of-key for sensitive actions is bypassed.
- Custom-method bypass. An attacker who can obtain or arrange the issuance of a SAML assertion bearing a non-standard confirmation method URI (a permissive STS that accepts arbitrary method strings, an experimental custom IDP, or an attacker-side construction that the issuer signs without validating the method field) can present the assertion and be authenticated. Per-method policies that an application or a binding-level policy expects the framework to enforce are silently bypassed.
Preconditions
The service is configured to accept SAML 1.1 tokens via federation. Typical bindings are WS2007FederationHttpBinding and WSFederationHttpBinding, or any custom binding using IssuedSecurityTokenParameters with a SAML 1.1 token type.
The attacker has obtained at least one signed SAML 1.1 assertion of a shape that triggers the bypass.
Patches
Fixed in CoreWCF v1.8.1 and v1.9.1
Workarounds
To exploit this issue, it's required that a trusted STS issues SAML assertions whose SubjectConfirmationMethod is not one of the SAML 1.1 trio, or is willing to issue holder-of-key assertions without KeyInfo. If no trusted STS is willing to issue SAML assertions meeting either of these criteria, then a service isn't vulnerable.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| .NETNuGet | CoreWCF.Primitives | all versions | 1.8.1 |
| .NETNuGet | CoreWCF.Primitives | ≥ 1.9.0&&< 1.9.1 | 1.9.1 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for CoreWCF.Primitives. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.
Fix
Update CoreWCF.Primitives to 1.8.1 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-48pq-2xq3-c2m4 is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
How O3 protects you
O3 pinpoints whether GHSA-48pq-2xq3-c2m4 is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.
Tailored to GHSA-48pq-2xq3-c2m4. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is GHSA-48pq-2xq3-c2m4 in your dependencies?
O3 detects GHSA-48pq-2xq3-c2m4 across NuGet dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.