CVE-2026-52842CWE-346

Lightpanda:URL parser misidentifies page origin for URLs containing @ in the path - Same-Origin Policy bypass

Critical · published July 15, 2026

CVSS v3.1
9.3
EPSS
0%
Percentile
15.0
In the wild
Unconfirmed
What it is

Lightpanda is a headless browser designed for AI and automation. Prior to 0.3.1, Lightpanda searched for @ across the entire URL string instead of only the authority component when computing a page origin, so a URL such as `http://attacker.com/@victim.com/` was fetched from attacker.com but treated as `http://victim.com`, allowing a complete Same-Origin Policy bypass. This issue is fixed in version 0.3.1.

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
0.00246 · 15.0th percentile
Weakness
CWE-346 · Origin Validation Error
Published
2026-07-15T16:18Z
EPSS history
Timeline
  • 15 JUL 16:18Z
    Lightpanda:URL parser misidentifies page origin for URLs containing @ in the path - Same-Origin Policy bypass
    cvelistv5