Critical severity · published Jul 15, 2026
CVE-2026-52843
Lightpanda: fetch() and XMLHttpRequest attach session cookies to cross-origin requests regardless of credentials mode
9.3
CVSS
0.2%
EPSS
No
On KEV
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.
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:N
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
Required
Confidentiality
High
Integrity
High
Availability
None
Scope
Changed
Exploitation
Is it being used?
Exploit prediction (EPSS)0.2% · higher than 14% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
BR
browser · lightpanda-io
< 0.2.9 · source: vendor
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-52843
CVE.org
https://www.cve.org/CVERecord?id=CVE-2026-52843
github.com
https://github.com/lightpanda-io/browser/commit/2cdaac780bed65db98bbb6ed2ad5bc6011863c76
github.com
https://github.com/lightpanda-io/browser/pull/2155
github.com
https://github.com/lightpanda-io/browser/releases/tag/0.2.9
github.com
https://github.com/lightpanda-io/browser/security/advisories/GHSA-36mm-v3c2-24cc
More from browser
9.3
CVE-2026-52842
Lightpanda:URL parser misidentifies page origin for URLs containing @ in the path - Same-Origin Policy bypass