Error handling for script execution was incorrectly isolated from web content, which could have allowed cross-origin leak attacks. This vulnerability affects Firefox < 139, Firefox ESR < 115.24, and Firefox ESR < 128.11.
CVE ID: CVE-2025-5263
CVSS Base Severity: MEDIUM
CVSS Base Score: 4.3
CVSS Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:N/A:N
Vendor: Mozilla
Product: Firefox, Firefox ESR
EPSS Score: 0.03% (probability of being exploited)
EPSS Percentile: 7.46% (scored less or equal to compared to others)
EPSS Date: 2025-06-18 (when was this score calculated)