CVE-2026-15719 Site isolation issue in the DOM: Navigation component

What is CVE-2026-15719?

CVE-2026-15719 is a medium-severity vulnerability in Mozilla Firefox, published on 14 Jul 2026. 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

We are aware that exploit code for this is public however we are not aware of any attacks in the wild abusing this flaw. This vulnerability was fixed in Firefox 152.0.6, Firefox ESR 115.38, Firefox ESR 140.13, and Thunderbird 140.13.

Which versions are affected by CVE-2026-15719?

It affects 1 product.

Products include Mozilla Firefox.

How do I fix CVE-2026-15719?

Upgrade to a fixed version.

Is CVE-2026-15719 being exploited?

There is no known exploitation of CVE-2026-15719 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-2026-15719, GHSA-hqh9-m4jx-3x67, UBUNTU-CVE-2026-15719.