CVE-2025-5263 Error handling for script execution was incorrectly isolated from web content
Attackers could perform cross-origin leak attacks due to incorrect isolation of script execution error handling in Firefox and Thunderbird.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- A user has to click or open something
- Fix
- Available
What is CVE-2025-5263?
CVE-2025-5263 is a medium-severity vulnerability in Mozilla Firefox, published on 27 May 2025. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.
Official description
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.
Weakness: CWE-346
Which versions are affected by CVE-2025-5263?
It affects 1 product.
Products include Mozilla Firefox.
How do I fix CVE-2025-5263?
Upgrade to a fixed version.
Is CVE-2025-5263 being exploited?
There is no known exploitation of CVE-2025-5263 in the wild and no public exploit code.
Other vulnerabilities in Mozilla Firefox
Sources
Also known as DEBIAN-CVE-2025-5263, GHSA-pjg4-cx24-6mjc, UBUNTU-CVE-2025-5263.