Lab: Reflected XSS with some SVG markup allowed
Summary: PortSwigger's lab presents a reflected cross-site scripting vulnerability where the site blocks common tags but fails to block some SVG tags and events. Using an Intruder payload position on the search term, all payloads returned a 400 response except the onbegin payload, which returned 200 and triggered the alert() function.
Key Takeaway: The blocklist missed an SVG event handler entirely, so a single unblocked tag name was enough to execute script - a reminder that tag-based filtering leaves the full set of SVG events as live attack surface.
Read the original at PortSwigger Research ↗
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