Summary
Unleash: Missing await on permission check + cross-project IDOR in admin API
Multiple authorization vulnerabilities in Unleash admin API, including a critical missing await that completely bypasses a permission check.
Vulnerability 1: Missing await on Permission Check (HIGH)
File: src/lib/features/segment/segment-controller.ts (line 345)
POST /api/admin/segments/strategies has permission: NONE at the route level. The handler performs its own check via this.accessService.hasPermission(), but omits the await keyword. Since hasPermission() is async (returns Promise<boolean>), the variable always receives a truthy Promise object. The if (!hasFeatureStrategyPermission) check never triggers.
// BUG: missing await - hasPermission() returns Promise<boolean>
const hasFeatureStrategyPermission = this.accessService.hasPermission(
req.user, UPDATE_FEATURE_STRATEGY, projectId, environmentId,
);
if (!hasFeatureStrategyPermission) { // Always false - Promise is truthy!
res.status(403).send();
return;
}
Impact: Any authenticated user can modify segment assignments on ANY strategy across ALL projects.
Fix: Add await: const hasFeatureStrategyPermission = await this.accessService.hasPermission(...)
Vulnerability 2: Cross-Project Variant Read (MEDIUM)
File: src/lib/routes/admin-api/project/variants.ts (line 213-223)
GET /api/admin/projects/:projectId/features/:featureName/environments/:environment/variants completely ignores projectId. getVariantsOnEnv() only uses featureName and environment.
Impact: Any authenticated user can read variant configs (names, weights, payloads) from any project.
Vulnerability 3: Cross-Project Strategy Read (MEDIUM)
File: src/lib/features/feature-toggle/feature-toggle-controller.ts (line 1107-1116)
GET .../strategies/:strategyId ignores all params except strategyId. Any authenticated user can read any strategy's full configuration.
Vulnerability 4: Cross-Project Environment Info Leak (MEDIUM)
File: src/lib/features/feature-toggle/feature-toggle-service.ts (line 1611)
getEnvironmentInfo() doesn't validate feature belongs to project. Compare with getFeature() which calls validateFeatureBelongsToProject().
Vulnerability 5: Cross-Project Tag Modification (LOW)
File: src/lib/features/feature-toggle/feature-toggle-controller.ts (line 576-596)
PUT /:projectId/tags accepts features array in body without validating they belong to projectId.
Impact
The application does not perform an authorization check before performing a sensitive operation. Typical impact: unauthorized access to restricted functionality or data.
Affected versions
Security releases
Kodem intelligence
Severity tells you how bad this could be in the worst case. It does not tell you whether you are exposed. Exploitability and impact are functions of runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A vulnerable package can sit in your dependency tree and never run.
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Frequently Asked Questions
- What is CVE-2026-77426? CVE-2026-77426 is a high-severity missing authorization vulnerability in unleash-server (npm), affecting versions < 8.0.3. It is fixed in 8.0.3. The application does not perform an authorization check before performing a sensitive operation.
- Which versions of unleash-server are affected by CVE-2026-77426? unleash-server (npm) versions < 8.0.3 is affected.
- Is there a fix for CVE-2026-77426? Yes. CVE-2026-77426 is fixed in 8.0.3. Upgrade to this version or later.
- Is CVE-2026-77426 exploitable, and should I be worried? Whether CVE-2026-77426 is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk. Get a demo
- What actually determines whether CVE-2026-77426 is exploitable, and how bad it is? Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.
- How do I fix CVE-2026-77426? Upgrade
unleash-serverto 8.0.3 or later.