fix(csp): support MemberExpression assignments in evaluator#4807
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calebporzio merged 2 commits intoalpinejs:mainfrom Apr 10, 2026
Merged
fix(csp): support MemberExpression assignments in evaluator#4807calebporzio merged 2 commits intoalpinejs:mainfrom
calebporzio merged 2 commits intoalpinejs:mainfrom
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Replace the blanket "Property assignments are prohibited" throw with targeted logic that resolves the object and property, blocks DOM node writes (instanceof Node), and performs the assignment. The UpdateExpression MemberExpression path was missing both guards; align it with AssignmentExpression to correctly guard against DOM node writes and prototype pollution. Fixes alpinejs#4722 Ref: alpinejs#4671 (sections 3.1.6, 3.2.5)
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- Add setAttribute, setAttributeNS, setAttributeNode, setAttributeNodeNS
to the dangerous keywords blocklist to prevent XSS via event handler
attribute injection (e.g. $el.setAttribute('onclick', 'evil'))
- Widen instanceof Node check to also cover CSSStyleDeclaration,
DOMStringMap, DOMTokenList, and NamedNodeMap to prevent property
assignments on DOM-adjacent objects (e.g. $el.style.cssText, $el.dataset)
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
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Replace the blanket "Property assignments are prohibited" throw with targeted logic that resolves the object and property, blocks DOM node writes (instanceof Node), and performs the assignment. The UpdateExpression MemberExpression path was missing both guards; align it with AssignmentExpression to correctly guard against DOM node writes and prototype pollution.
Fixes #4722
Ref: #4671 (sections 3.1.6, 3.2.5)