CVE-2026-52843: Lightpanda-Io Browser

Critical severity, CVSS 9.3. EPSS: 0.2% chance of exploitation in the next 30 days.

Lightpanda is a headless browser designed for AI and automation. Prior to 0.2.9, Lightpanda fetch() and XMLHttpRequest unconditionally attached session cookies to every HTTP request, ignoring credentials: omit, credentials: same-origin, credentials: include, and XMLHttpRequest.withCredentials, allowing an attacker-controlled origin in a Lightpanda session to issue authenticated cross-origin requests against a victim origin. This issue is fixed in version 0.2.9.

Affected products

• Lightpanda-Io Browser: before 0.2.9 (fixed in 0.2.9)

Published 2026-07-15. Last modified 2026-07-15.