CVE-2025-5263

Description

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, Firefox ESR < 128.11, Thunderbird < 139, and Thunderbird < 128.11.

Category

4.3
CVSS
Severity: Medium
CVSS 3.1 •
EPSS 0.02%
Vendor Advisory mozilla.org Vendor Advisory mozilla.org Vendor Advisory mozilla.org
Affected: Mozilla Firefox
Affected: Mozilla Firefox ESR
Affected: Mozilla Firefox ESR
Affected: Mozilla Thunderbird
Affected: Mozilla Thunderbird
Published at:
Updated at:

References

Link Tags
https://bugzilla.mozilla.org/show_bug.cgi?id=1960745 permissions required
https://www.mozilla.org/security/advisories/mfsa2025-42/ vendor advisory
https://www.mozilla.org/security/advisories/mfsa2025-43/ vendor advisory
https://www.mozilla.org/security/advisories/mfsa2025-44/ vendor advisory
https://www.mozilla.org/security/advisories/mfsa2025-45/
https://www.mozilla.org/security/advisories/mfsa2025-46/

Frequently Asked Questions

What is the severity of CVE-2025-5263?
CVE-2025-5263 has been scored as a medium severity vulnerability.
How to fix CVE-2025-5263?
To fix CVE-2025-5263, make sure you are using an up-to-date version of the affected component(s) by checking the vendor release notes. As for now, there are no other specific guidelines available.
Is CVE-2025-5263 being actively exploited in the wild?
As for now, there are no information to confirm that CVE-2025-5263 is being actively exploited. According to its EPSS score, there is a ~0% probability that this vulnerability will be exploited by malicious actors in the next 30 days.
What software or system is affected by CVE-2025-5263?
CVE-2025-5263 affects Mozilla Firefox, Mozilla Firefox ESR, Mozilla Firefox ESR, Mozilla Thunderbird, Mozilla Thunderbird.
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