Sandbox Escape Vulnerability in Firefox by Mozilla
CVE-2026-100787

Currently unrated

Key Information:

Vendor: Mozilla
Status: Firefox
Vendor: CVE Published:; 29 September 2026

What is CVE-2026-100787?

A sandbox escape vulnerability exists within the XUL component of Mozilla Firefox. This flaw may allow an attacker to bypass security mechanisms designed to isolate web content from the user's system, potentially exposing sensitive data or enabling malicious actions. Users are advised to update to Firefox ESR version 153.4 or Firefox version 157 to mitigate this risk.

Affected Version(s)

Firefox 153.4

Firefox 157

References

https://bugzilla.mozilla.org/show_bug.cgi?id=2071068

https://www.mozilla.org/security/advisories/mfsa2026-100/

https://www.mozilla.org/security/advisories/mfsa2026-97/

Download the Critical Vulnerability Management Cheat Sheet

Timeline

Vulnerability published
Sep 29, 2026
Vulnerability Reserved
Sep 26, 2026

Credit

Mozilla

CVE-2026-100787 Data

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