fix(security): sanitize markdown in RenderMarkdownContent to prevent XSS — #190#214
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Jagadeeshftw merged 2 commits intoJun 23, 2026
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IssuesTab renders external GitHub discussion content through react-markdown with no sanitization, creating an XSS vector. Adds rehype-sanitize with a strict protocol allowlist (http, https, mailto only) that blocks javascript: and data: URLs in links and image sources while preserving safe markup. Closes Grainlify#190 Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
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sanitizing the markdown via rehype-sanitize is an important xss hardening for RenderMarkdownContent, good catch. rebased on latest main and confirmed the new dep resolves cleanly. thanks! |
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Summary
RenderMarkdownContentrendered external GitHub discussion content throughreact-markdownwith no sanitization — a direct XSS vector viajavascript:ordata:links.rehype-sanitizewith a strict protocol allowlist: onlyhttp,https, andmailtoare permitted inhref/srcattributes. All other schemes (includingjavascript:anddata:) are stripped.defaultSchemaas the base so all standard safe HTML is still rendered correctly.Test plan
javascript:alert(1)links are stripped from rendered outputdata:text/html,...image sources are blockedrehype-sanitizewas already a transitive dep ofreact-markdownCloses #190
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