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Not in CISA KEV
LOW severity

GHSA-4v55-cpmv-3vcm

LOW

GHSA-4v55-cpmv-3vcm is a low-severity (CVSS 3.7) Broken Cryptographic Algorithm vulnerability in CoreWCF.Primitives. O3 Security confirms whether GHSA-4v55-cpmv-3vcm is actually reachable in your code before you act, and blocks exploitation at runtime until you patch.

CoreWCF: WS-Security Reference DigestMethod Algorithm-Suite Bypass

Also known asCVE-2026-54780
Published
Jun 19, 2026
Updated
Jun 19, 2026
Affected
2 pkgs
Patched
2 / 2
Exploits
None indexed
Exploitation data as of Sep 8, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

Exploitation Status

No confirmed exploitation observed yet

  • 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-4v55-cpmv-3vcm.

EPSS Exploitation Probability

via FIRST.org ↗
0.2%probability of exploitation in next 30 days
Lower Risk0.00%
Lower risk than most CVEs15th percentile — riskier than 15% of all scored CVEsHighest risk
0.00%0.25%0.49%0.74%0.2%0.2%0.2%Aug 26Sep 26Sep 26

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-4v55-cpmv-3vcm 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 369,023 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

2 pkgs affected
.NETCoreWCF.Primitives.NETCoreWCF.Primitives

Real-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

CoreWCF’s WS-Security 1.0 receive pipeline validates the SignatureMethod of an incoming ds:SignedInfo against the configured SecurityAlgorithmSuite, but does not validate the DigestMethod declared on each ds:Reference. As a result, a sender can populate ds:SignedInfo with SignatureMethod values the suite accepts (for example rsa-sha256 under Basic256Sha256) while declaring a per-reference DigestMethod the suite rejects (for example http://www.w3.org/2000/09/xmldsig#sha1). The signature is then verified where it permits SHA-1 digests, and the message is accepted.

Patches

Fixed in CoreWCF v1.8.1 and v1.9.1

Workarounds

None

Affected Packages

2 total 2 fixed
EcosystemPackageVulnerable rangeFix
.NETNuGetCoreWCF.Primitivesall versions1.8.1
.NETNuGetCoreWCF.Primitives1.9.0&&< 1.9.11.9.1

Detection & mitigation playbook

Open-source dependency
  1. Detect

    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.

  2. 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-4v55-cpmv-3vcm is resolved across your whole dependency graph.

  3. 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.

  4. How O3 protects you

    O3 pinpoints whether GHSA-4v55-cpmv-3vcm 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-4v55-cpmv-3vcm. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.

Frequently Asked Questions

### Impact CoreWCF’s WS-Security 1.0 receive pipeline validates the `SignatureMethod` of an incoming `ds:SignedInfo` against the configured `SecurityAlgorithmSuite`, but does not validate the `DigestMethod` declared on each `ds:Reference`. As a result, a sender can populate `ds:SignedInfo` with `SignatureMethod` values the suite accepts (for example rsa-sha256 under Basic256Sha256) while declaring a per-reference `DigestMethod` the suite rejects (for example http://www.w3.org/2000/09/xmldsig#sha1). The signature is then verified where it permits SHA-1 digests, and the message is accepted. ###
O3 Security · Impact-Aware SCA

Is GHSA-4v55-cpmv-3vcm in your dependencies?

O3 detects GHSA-4v55-cpmv-3vcm across NuGet dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.

GHSA-4v55-cpmv-3vcm: CoreWCF.Primitives… | O3 Security