CVE-2025-10529 Same-origin policy bypass in the Layout component

What is CVE-2025-10529?

CVE-2025-10529 is a medium-severity vulnerability in Mozilla Firefox, published on 16 Sep 2025. An attacker can exploit it over the internet without logging in, with no action from the victim.

Official description

Same-origin policy bypass in the Layout component. This vulnerability was fixed in Firefox 143, Firefox ESR 140.3, Thunderbird 143, and Thunderbird 140.3.

Weakness: CWE-942

Which versions are affected by CVE-2025-10529?

It affects 2 products.

Products include Mozilla Firefox, Mozilla Thunderbird.

How do I fix CVE-2025-10529?

Upgrade to a fixed version.

Is CVE-2025-10529 being exploited?

There is no known exploitation of CVE-2025-10529 in the wild and no public exploit code.

Other vulnerabilities in Mozilla Firefox

• CVE-2019-11708 Mozilla Firefox and Thunderbird Sandbox Escape Exploited Critical 10.0
• CVE-2010-3765 Mozilla Multiple Products Remote Code Execution Exploited Critical 9.8
• CVE-2022-26486 Mozilla Firefox Use-After-Free Exploited Critical 9.6
• CVE-2022-26485 Mozilla Firefox Use-After-Free Exploited High 8.8
• CVE-2019-11707 Mozilla Firefox and Thunderbird Type Confusion Exploited High 8.8

All Mozilla Firefox vulnerabilities

Sources

• CVE record
• NVD
• OSV
• GitHub advisory
• How this page is made

Also known as DEBIAN-CVE-2025-10529, GHSA-9qv5-m6vr-vh73, UBUNTU-CVE-2025-10529.