MediumVulnerability
GHSA-w5cr-2qhr-jqc5: Cloudflare Agents has a Reflected Cross-Site Scripting (XSS) vulnerability in AI Playground site
- Identifier
- GHSA-w5cr-2qhr-jqc5
- Published
- Record updated
- Affected
- agents < 0.3.10
- Fixed in
- 0.3.10
- released February 4, 2026, 9 days before disclosure
Summary
Cloudflare Agents' AI Playground OAuth callback handler in site/ai-playground/src/server.ts inserted the error_description query parameter into an inline script tag without escaping. A crafted link lets an attacker run JavaScript in a victim's session, exposing chat history, LLM interactions and connected MCP servers, and enabling actions on the victim's behalf.
Mitigation
Agents-sdk users should upgrade to agents@0.3.10 (fix in PR https://github.com/cloudflare/agents/pull/841). Developers using configureOAuthCallback with custom error handling should escape all user-controlled input before interpolation.
Topics
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