CVE-2026-52843CWE-346

Lightpanda: fetch() and XMLHttpRequest attach session cookies to cross-origin requests regardless of credentials mode

Critical · published July 15, 2026

CVSS v3.1
9.3
EPSS
0%
Percentile
13.5
In the wild
Unconfirmed
What it is

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.

The record
Technical detail
CVSS v3.1
9.3 · CRITICAL
Vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:N
CVSS v4.0
Not supplied
EPSS
0.00234 · 13.5th percentile
Weakness
CWE-346 · Origin Validation Error
Published
2026-07-15T16:16Z
EPSS history
Timeline
  • 15 JUL 16:16Z
    Lightpanda: fetch() and XMLHttpRequest attach session cookies to cross-origin requests regardless of credentials mode
    cvelistv5