CVE-2026-91942: crawl4ai before 0.9.3 Cross-Site Scripting via innerHTML
crawl4ai before 0.9.3 contains a DOM-based cross-site scripting vulnerability in the Docker Playground UI that assigns untrusted crawl results to element.innerHTML. Attackers can craft malicious PDFs with event-handler markup to execute JavaScript in the Playground origin and steal API tokens from sessionStorage for authenticated API abuse.
Affected Software
Event History
Frequently Asked Questions
Which deployments are exposed?
The affected component is the Docker Playground UI in crawl4ai versions before 0.9.3. Exposure occurs when the Playground renders untrusted crawl results, including malicious PDFs containing event-handler markup.
What must an attacker do to exploit this issue?
An attacker must provide a crafted PDF or other crawl result containing malicious markup that reaches the Playground UI. Exploitation also requires user interaction, as indicated by the UI:R vector.
What is the practical impact of successful exploitation?
JavaScript can execute in the Playground origin and access API tokens stored in sessionStorage. Those tokens can then be used for authenticated API abuse.
How can I determine whether I am affected?
Check whether crawl4ai is running a version earlier than 0.9.3 and whether the Docker Playground UI is used to display crawl results. Systems meeting both conditions should be treated as affected.