fix: HTML-escape all user data in slide generator to prevent stored XSS#274
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TemaDeveloper wants to merge 1 commit intonextlevelbuilder:mainfrom
Open
fix: HTML-escape all user data in slide generator to prevent stored XSS#274TemaDeveloper wants to merge 1 commit intonextlevelbuilder:mainfrom
TemaDeveloper wants to merge 1 commit intonextlevelbuilder:mainfrom
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Add html.escape() to all 46 user-controlled data.get() calls across all 7 slide generator functions (title, problem, solution, metrics, chart, testimonial, cta) and the deck title. Add URL scheme validation for cta_url href to block javascript: URI injection. Closes nextlevelbuilder#247
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Summary
Fixes the Stored XSS vulnerability (CVSS 8.1) in
generate-slide.pyreported in #247.data.get()calls across all 7 slide generator functions usinghtml.escape()— prevents<script>,<img onerror>, and<iframe>injection into generated HTMLcta_urlin the CTA slide — blocksjavascript:URI injection by only allowinghttp://,https://,#, and/schemes<title>in the template rendering to prevent metadata injectionvaluetoint()in the style attribute to prevent CSS injection via theheightpropertyApproach
Added two small helpers at the top of the file:
_e(value, default)— wrapshtml.escape(str(...))for all content injection points_safe_url(url, default)— validates URL scheme before escaping forhrefattributesTesting
Verified with the exact PoC payload from #247:
<script>alert('XSS')</script>in title → rendered as escaped text<img src=x onerror=alert(1)>in badge → rendered as escaped textjavascript:alert(document.domain)in cta_url → replaced with#Closes #247