CVE-2026-8390 Use-after-free in the JavaScript: WebAssembly component

What is CVE-2026-8390?

CVE-2026-8390 is a high-severity use after free vulnerability in Mozilla Firefox, published on 12 May 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

Official description

Use-after-free in the JavaScript: WebAssembly component. This vulnerability was fixed in Firefox 150.0.3.

Weakness: CWE-825, CWE-416

Which versions are affected by CVE-2026-8390?

It affects 1 product.

Products include Mozilla Firefox.

How do I fix CVE-2026-8390?

No fix has been published for CVE-2026-8390 yet. Limit exposure of the affected software until one is available.

Upgrade to the fixed version. These bugs are found with fuzzing and sanitisers and avoided by memory-safe languages. More about Use after free.

Is CVE-2026-8390 being exploited?

There is no known exploitation of CVE-2026-8390 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 GHSA-ggqh-jgm2-3w29, UBUNTU-CVE-2026-8390.