CVE-2025-5263
MediumCVSS 4.3Exploitation Probability (EPSS)
Low risk15th percentile - higher than 15% of all known CVEs
Summary
Error handling for script execution was incorrectly isolated from web content, which could have allowed cross-origin leak attacks. This vulnerability was fixed in Firefox 139, Firefox ESR 115.24, Firefox ESR 128.11, Thunderbird 139, and Thunderbird 128.11.
Risk Assessment
An attacker could exploit this vulnerability to leak information across origins, potentially exposing sensitive user data.
Recommendation
Update Firefox and Thunderbird to the latest versions (Firefox 139, Firefox ESR 115.24/128.11, Thunderbird 139/128.11 or later).
Other vulnerabilities in Firefox
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Sandbox escape due to incorrect boundary conditions in the Widget: Win32 component. The flaw was fixed in Firefox 158, Firefox ESR 153.5, Thunderbird 158, and Thunderbird 153.5.
Original NVD description (English source)
Error handling for script execution was incorrectly isolated from web content, which could have allowed cross-origin leak attacks. This vulnerability was fixed in Firefox 139, Firefox ESR 115.24, Firefox ESR 128.11, Thunderbird 139, and Thunderbird 128.11.
Vulnerability data from NVD (NIST) · CISA KEV · EPSS