CVE-2026-52843 Lightpanda: fetch() and XMLHttpRequest attach session cookies to cross-origin requests regardless of credentials mode
Lightpanda browser ignores cookie security policies, allowing attackers to send session cookies to cross-origin sites and access victim data.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- A user has to click or open something
- Fix
- None listed
What is CVE-2026-52843?
CVE-2026-52843 is a critical vulnerability in lightpanda-io browser, published on 15 Jul 2026. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.
Official description
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.
Weakness: CWE-346
Which versions are affected by CVE-2026-52843?
How do I fix CVE-2026-52843?
No fix has been published for CVE-2026-52843 yet. Limit exposure of the affected software until one is available.
Is CVE-2026-52843 being exploited?
There is no known exploitation of CVE-2026-52843 in the wild and no public exploit code.
Sources
Also known as GHSA-36mm-v3c2-24cc.