Nexus — Workout & Nutrition Tracker

• Outcome: Pass
• Latest audit: Sep 16, 2026 · 5:29 AM UTC
• Version: 1.1.0

Overview

The skill matches its stated fitness-tracking purpose, but users should understand it uploads sensitive fitness data and installs an external CLI package.

Before installing, verify that `nexus-fitness` is the package you intend to trust, review the linked privacy policy, and avoid logging fitness, meal, weight, or friend-linked details you would not want stored in the Nexus cloud account.

A.I.G

Vulnerability Patterns

• Insecure Dependencies: Introduces malicious components through unsafe dependency sources
• Skill Instruction Hijacking: Alters the agent's session goals or safety constraints when the skill loads
• Agent Memory Poisoning: Writes attacker-controlled rules into memory that affect later sessions
• Remote Payload Retrieval and Execution: Fetches external code whose behavior can change after review
• Embedded Malicious Code: Ships malicious scripts inside the skill and executes them locally

Findings (1)

T08 · Insecure Dependencies

Warning

• Location: SKILL.md:8

Finding

Unpinned Third-Party CLI Dependency

Content

View full analysis

Vulnerability Details

File Location: SKILL.md, lines 8–10
Vulnerability Type: Unpinned third-party package installation
Risk Level: Medium

Vulnerable Code:

bash

uv tool install nexus-fitness

Technical Analysis

The installation instructions retrieve and execute the latest available release of the third-party nexus-fitness package without specifying a reviewed version or verifying an integrity hash or signature. Consequently, the code installed when a user follows these instructions may differ from the code that existed when this Skill was audited.

Because the package implementation is not included in the project, its runtime behavior cannot be verified from the audited artifact. A compromised package registry account, malicious maintainer release, package replacement, or supply-chain compromise could cause attacker-controlled code to execute under the installing user's account.

Attack Path

1. An attacker compromises the nexus-fitness package, its maintainer account, or an upstream build and publication process.
2. The attacker publishes a malicious release under the expected package name.
3. A user follows the Skill's unpinned uv tool install nexus-fitness instruction.
4. The package manager resolves and installs the attacker-controlled release.
5. Malicious code executes during installation or when the user invokes the installed nexus CLI.
6. The code operates with the privileges of the invoking user and may access resources available to that account.

Impact Assessment

Successful exploitation could permit arbitrary code execution with the installing or invoking user's privileges. Depending on that user's environment, the malicious package could access local files, environment variables, authentication material, Nexus or Google session tokens, and sensitive fitness data. It could also alter user-owned files or communicate captured data to external systems.

No evidence ...[truncated 136 chars]

Remediation

View remediation

Remediation Suggestions

• Pin nexus-fitness to a specific version that has undergone security review, for example:

  bash

  uv tool install "nexus-fitness==X.Y.Z"
  

• Verify the package artifact using a trusted cryptographic hash or signature where supported.
• Document the authoritative registry, publisher identity, and source repository so users can verify package provenance.
• Review each version before updating the pinned dependency, including its transitive dependencies and release artifacts.
• Consider vendoring or including the relevant source code in the auditable project when practical.
• Use an isolated, least-privilege environment for installation and execution, and avoid exposing unrelated credentials or sensitive files to the CLI.

SkillSpector

Vulnerability Patterns

• Data Exfiltration: External Transmission, Env Variable Harvesting, File System Enumeration
• Prompt Injection: Instruction Override, Hidden Instructions, Exfiltration Commands
• Privilege Escalation: Excessive Permissions, Sudo/Root Execution, Credential Access
• Supply Chain: Unpinned Dependencies, External Script Fetching, Obfuscated Code
• Excessive Agency: Unrestricted Tool Access, Autonomous Decision Making, Scope Creep

Findings (1)

Missing User Warnings

Medium

• Category: Not specified by scanner
• Confidence: 92% confidence

Finding

The skill explicitly says fitness data is stored in the cloud, but it does not prominently warn users that workouts, meals, weight, and friend-linked history are sensitive personal data that may create privacy exposure. Users may disclose health-adjacent information without understanding retention, sharing, and third-party access implications, especially given the social 'friends' feature and cloud storage model.

Content

No source excerpt is available for this finding.

Static analysis

No suspicious patterns detected.