SECURITY REPORT · EXTENSHI SCAN
Custom Site JS
Firefox extension·by David Hicken
0
/ 100 SAFETY SCORE
DANGEROUS
Meaningful risk surface. Avoid on managed devices without review.
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
Custom Site JS's safety score vs every other extension we've scanned
Globally
14%of extensions carry more risk
Riskier ←→ Safer
Ranked against 369,936 extensions
In Appearance
3%of appearance extensions carry more risk
Riskier ←→ Safer
Ranked against 17,915 appearance extensions
Findings
20
median 3Lower is safer
Critical findings
1
median 0Severity = Critical
Permissions
4
median 2Declared in manifest
Active users
201
median 3vs category median
Findings breakdown
Automated security signal · 20 distinct issues across 6 severities
20
distinct issues
detected
detected
Scanners reported 27 raw occurrences; repeats of the same issue at the same location are merged here. The list below shows every occurrence.
Critical15%
High945%
Needs Review00%
Medium840%
Low210%
Info00%
Permissions requested
1 risky permission of 4 total
1 high-risk permission require attention
This extension requests 4 permissions in total. 1 of them grant broad capabilities that are worth a careful look.
High
View open tabs
Can see URLs and titles of all open tabs
Medium
Monitor navigation
Can observe and track tab navigation events and URL changes
Medium
Store local data
Can save data locally in the browser for persistence
Info
*://*/*
No additional information available.
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Scan performed by extenshi.io · Aug 3, 2026
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