T09 · Insecure Skill Coding Practices
- Location
src/index.js:130- Finding
Infinite Loop in Dependency Scheduling Enables Denial of Service
- Content
View full analysis
Vulnerability Details
File Location:
src/index.js, lines 130–149
Vulnerability Type: Improper validation of cyclic or unsatisfiable dependency graphs
Risk Level: MediumVulnerable Code
javascript while (remainingNodes.length > 0) { const currentLevel = remainingNodes.filter(node => { const deps = graph[node]; return deps.every(dep => visited.has(dep)); }); if (currentLevel.length > 0) { groups.push(currentLevel); currentLevel.forEach(node => visited.add(node)); } remainingNodes = remainingNodes.filter(node => !visited.has(node)); } return groups;Technical Analysis
identifyParallelGroups()repeatedly searches for dependency-graph nodes whose dependencies have already been visited. It does not detect cases in which no remaining node can be scheduled.If the graph contains a cycle, self-dependency, or reference to a nonexistent node,
currentLevelcan remain empty. In that state:- No node is added to
visited. - The contents of
remainingNodesdo not change. - The loop condition remains true indefinitely.
Because this is a synchronous loop, it blocks the Node.js event loop and continuously consumes CPU. The public
orchestrate()function passes caller-supplied subtasks into this logic without validating dependency indices or verifying that the graph is acyclic.Attack Path
-
An attacker or untrusted upstream component supplies subtasks containing cyclic dependencies:
javascript const subtasks = [ { name: 'A', type: 'analysis', dependsOn: [1] }, { name: 'B', type: 'writing', dependsOn: [0] } ]; -
The application calls:
javascript orchestrate(subtasks, skillMapping); -
buildDependencyGraph()accepts the dependency relationships without validation. -
identifyParallelGroups()cannot find a node whose dependencies h ...[truncated 881 chars]
- No node is added to
- Remediation
View remediation
Remediation Suggestions
-
Validate every subtask before graph construction:
- Require
dependsOnto be an array. - Require each dependency to be an integer.
- Reject negative or out-of-range indices.
- Reject direct self-dependencies.
- Require
-
Detect cyclic graphs with a standard topological-sorting algorithm, such as Kahn's algorithm or depth-first search with node states.
-
Add an explicit progress guard to the existing loop:
javascript if (currentLevel.length === 0) { throw new Error( 'Dependency graph contains a cycle or an unsatisfied dependency' ); } -
Return a controlled validation error instead of continuing execution when the graph is invalid.
-
Add automated tests covering:
- Two-node and multi-node cycles.
- Self-dependencies.
- References to nonexistent nodes.
- Negative, fractional, string, and null dependency values.
- Valid disconnected directed acyclic graphs.
-
Where this function is exposed through a service, enforce input-size limits and execution timeouts as defense-in-depth controls.
-