LLM Output XSS — Eliciting JavaScript Payloads from LLM for Browser Injection - ATR-2026-00516 (952708a4-8040-54f8-9540-a645269b8460)
Detects attempts to elicit JavaScript/HTML XSS payloads from an LLM that will be rendered unsanitized in a browser context. OWASP LLM05:2025 Improper Output Handling. The attack asks the LLM to produce output containing script tags, event-handler attributes (onerror=, onload=, onclick=), javascript: URIs, or data:text/html URIs with malicious payloads (cookie theft, localStorage dump, content exfiltration). This rule targets the REQUEST side — prompts asking the LLM to GENERATE these payloads, not the payloads themselves in transit. Patterns: request-verb + XSS-payload-fragment (script tag, event handler, javascript: URI, data URI) co- occurring with exfil targets (cookie, localStorage, sessionStorage, document body).