CVE-2026-100788 Invalid pointer in the JavaScript: WebAssembly component
An invalid pointer in the WebAssembly component allows attackers to execute arbitrary code via crafted web content.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-100788?
CVE-2026-100788 is a critical memory corruption vulnerability in Mozilla Firefox, published on 29 Sep 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official description
Invalid pointer in the JavaScript: WebAssembly component. This vulnerability was fixed in Firefox ESR 153.4, Thunderbird 157, Thunderbird 140.17, Thunderbird 153.4, Firefox 157, and Firefox ESR 140.17.
Weakness: CWE-824
Which versions are affected by CVE-2026-100788?
It affects 2 products.
Products include Mozilla Firefox, Mozilla Thunderbird.
How do I fix CVE-2026-100788?
Upgrade to a fixed version.
Upgrade to the fixed version. Memory-safe languages, compiler hardening and fuzzing prevent most new cases. More about Memory corruption.
Is CVE-2026-100788 being exploited?
There is no known exploitation of CVE-2026-100788 in the wild and no public exploit code.
Other vulnerabilities in Mozilla Firefox
Sources
Also known as DEBIAN-CVE-2026-100788, GHSA-q45r-899q-qwvr, UBUNTU-CVE-2026-100788.