SECURITY REPORT · EXTENSHI SCAN
CustomCSS Injector
Firefox extension·by Blizz3
0
/ 100 SAFETY SCORE
RISKY
Several elevated signals. Read the findings before sharing this with your team.
Likely abandonedsafety score reduced by 30 points
- No update in over 6 years
Why this matters
An unmaintained extension keeps whatever flaws it shipped with, and a listing with users but no owner is an attractive target to buy and repurpose.
Automated analysis of publicly available code — not a professional security audit. It may produce false positives and does not prove an extension is unsafe or safe. Treat it as one signal among many. Disclaimer · Report an issue
How it ranks
CustomCSS Injector's safety score vs every other extension we've scanned
Globally
18%of extensions carry more risk
Riskier ←→ Safer
Ranked against 369,936 extensions
In Social & Communication
8%of social & communication extensions carry more risk
Riskier ←→ Safer
Ranked against 12,741 social & communication extensions
Findings
16
median 4Lower is safer
Critical findings
1
median 0Severity = Critical
Permissions
4
median 3Declared in manifest
Active users
790
median 3vs category median
Findings breakdown
Automated security signal · 16 distinct issues across 6 severities
16
distinct issues
detected
detected
Critical16%
High16%
Needs Review00%
Medium1169%
Low319%
Info00%
Permissions requested
1 risky permission of 4 total
1 critical permission require attention
This extension requests 4 permissions in total. 1 of them grant broad capabilities that are worth a careful look.
Critical
Access to all websites
Can read and modify content on every website you visit
Medium
Store local data
Can save data locally in the browser for persistence
Medium
Add context menu items
Can add custom items to the right-click context menu
Medium
Show notifications
Can display desktop notifications outside the browser
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Scan performed by extenshi.io · Aug 3, 2026
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