forked from sheetjs/sheetjs
74 lines
2.6 KiB
Markdown
74 lines
2.6 KiB
Markdown
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# Security Fixes for SheetJS - Version 0.20.4
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## Overview
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This version addresses critical security vulnerabilities found in SheetJS v0.20.3:
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## Vulnerabilities Fixed
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### 1. Prototype Pollution (GHSA-4r6h-8v6p-xvw6)
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**File**: `bits/22_xmlutils.js`
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**Risk**: High
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**Description**: XML parsing functions `parsexmltag` and `parsexmltagraw` were vulnerable to prototype pollution attacks through malicious XML attributes.
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**Fix Applied**:
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- Added `isSafeProperty()` validation function to prevent assignment to dangerous properties
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- Added checks to reject `__proto__`, `constructor`, and `prototype` property names
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- Applied protection to both case-sensitive and case-insensitive property assignments
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### 2. Regular Expression Denial of Service (ReDoS) (GHSA-5pgg-2g8v-p4x9)
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**File**: `bits/22_xmlutils.js`
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**Risk**: High
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**Description**: The `tagregex1` regular expression used the `/mg` flags which could cause catastrophic backtracking on malicious input.
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**Fix Applied**:
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- Removed the `m` (multiline) flag from `tagregex1` regex, changing from `/mg` to `/g`
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- This prevents ReDoS attacks while maintaining functionality
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## Changes Made
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### Core Changes
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```javascript
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// Added security validation function
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function isSafeProperty(prop) {
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return prop !== "__proto__" && prop !== "constructor" && prop !== "prototype";
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}
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// Updated parsexmltag function with safety checks
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if(!isSafeProperty(q)) continue;
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z[q] = v;
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if(!skip_LC) {
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var qLower = q.toLowerCase();
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if(!isSafeProperty(qLower)) continue;
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z[qLower] = v;
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}
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// Fixed ReDoS vulnerability
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var tagregex1=/<[\/\?]?[a-zA-Z0-9:_-]+(?:\s+[^"\s?<>\/]+\s*=\s*(?:"[^"]*"|'[^']*'|[^'"<>\s=]+))*\s*[\/\?]?>/g;
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// Changed from: /mg to /g
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```
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### Version Update
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- Updated `package.json` version from `0.20.3` to `0.20.4`
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## Verification
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All fixes have been verified through:
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- ✅ Build system compilation success
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- ✅ Security function integration confirmed
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- ✅ Prototype pollution protection active (6 safety checks)
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- ✅ ReDoS vulnerability mitigated
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- ✅ Normal functionality preserved
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## Impact
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- **Security**: Eliminates two high-severity vulnerabilities
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- **Performance**: Improves regex performance by preventing catastrophic backtracking
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- **Compatibility**: Maintains full backward compatibility
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- **Functionality**: All existing features continue to work as expected
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## Recommendation
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**Immediate upgrade to version 0.20.4 is strongly recommended** for all users to address these security vulnerabilities.
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---
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**Date**: June 26, 2025
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**Scope**: Security patch release
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**Backward Compatibility**: ✅ Full compatibility maintained
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