Is Metamask Legacy Web3 Safe?
Metamask Legacy Web3 — Nerq Trust Score 50.5/100 (C- grade). Based on analysis of 2 trust dimensions, it is has notable safety concerns. Last updated: 2026-05-21.
Use Metamask Legacy Web3 with some caution. Metamask Legacy Web3 is a Firefox extension with a Nerq Trust Score of 50.5/100 (C-), based on 3 independent data dimensions. Below the recommended threshold of 70. Security: 90/100. Popularity: 15/100. Data sourced from addons.mozilla.org metadata, permissions analysis, and source code availability. Last updated: 2026-03-22. Machine-readable data (JSON).
Is Metamask Legacy Web3 safe?
CAUTION — Metamask Legacy Web3 has a Nerq Trust Score of 50.5/100 (C-). It has moderate trust signals but shows some areas of concern that warrant attention. Suitable for development use — review security and maintenance signals before production deployment.
What is Metamask Legacy Web3's trust score?
Metamask Legacy Web3 has a Nerq Trust Score of 50.5/100, earning a C- grade. This score is based on 2 independently measured dimensions including security, maintenance, and community adoption.
What are the key security findings for Metamask Legacy Web3?
Metamask Legacy Web3's strongest signal is security at 90/100. No known vulnerabilities have been detected. It has not yet reached the Nerq Verified threshold of 70+.
What is Metamask Legacy Web3 and who maintains it?
| Author | danfinlay |
| Category | Firefox Add-ons |
| Source | N/A |
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Safety Guide: Metamask Legacy Web3
What is Metamask Legacy Web3?
Metamask Legacy Web3 is a Firefox add-on — Adds MetaMask's legacy window.web3 API to your browser.
How to Verify Safety
Review permissions on addons.mozilla.org. Check if source code is available.
You can also check the trust score via API: GET /v1/preflight?target=MetaMask Legacy Web3
Key Safety Concerns for Firefox add-on
When evaluating any Firefox add-on, watch for: excessive permissions, data harvesting.
Trust Assessment
Metamask Legacy Web3 has a Nerq Trust Score of 50/100 (C-) and has not yet reached Nerq trust threshold (70+). This score is based on automated analysis of security, maintenance, community, and quality signals.
Key Takeaways
- Metamask Legacy Web3 has a Trust Score of 50/100 (C-).
- Review carefully before use — below trust threshold.
- Always verify independently using the Nerq API.
Detailed Score Analysis
| Dimension | Score |
|---|---|
| Security | 90/100 |
| Maintenance | 50/100 |
| Popularity | 15/100 |
| Quality | 40/100 |
| Community | 35/100 |
Based on 5 dimensions. Data from addons.mozilla.org metadata, permissions analysis, and source code availability.
What data does Metamask Legacy Web3 collect?
Privacy assessment for Metamask Legacy Web3 is not yet available. See our methodology for how Nerq measures privacy, or the public privacy review for any community-contributed notes.
Is Metamask Legacy Web3 secure?
Security score: 90/100. This meets the recommended security threshold for production use.
Nerq monitors this entity against NVD, OSV.dev, and registry-specific vulnerability databases for ongoing security assessment.
Full analysis: Metamask Legacy Web3 Security Report
How we calculated this score
Metamask Legacy Web3's trust score of 50.5/100 (C-) is computed from addons.mozilla.org metadata, permissions analysis, and source code availability. The score reflects 5 independent dimensions: security (90/100), maintenance (50/100), popularity (15/100), quality (40/100), community (35/100). Each dimension is weighted equally to produce the composite trust score.
Nerq analyzes over 7.5 million entities across 26 registries using the same methodology, enabling direct cross-entity comparison. Scores are updated continuously as new data becomes available.
This page was last reviewed on May 21, 2026. Data version: 0.0.
Full methodology documentation · Machine-readable data (JSON API)
Frequently Asked Questions
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Disclaimer: Nerq trust scores are automated assessments based on publicly available signals. They are not endorsements or guarantees. Always conduct your own due diligence.