Widespread browser (Firefox/ESR) vulnerability; sandbox escape enabling RCE from web content could impact enterprise endpoints and user systems.
CVE-2026-100762
Use-after-free in DOM allows Firefox sandbox escape and potential remote code execution.
Is CVE-2026-100762 being exploited?
Not confirmed. CVE-2026-100762 does not appear in CISA's Known Exploited Vulnerabilities catalog, which records only exploitation that has been observed and reported publicly. That is evidence of absence of a report, not evidence the flaw is unattacked.
How severe is CVE-2026-100762?
CVE-2026-100762 is rated Critical with a CVSS score of 9.6. Severity describes how bad exploitation would be, not how likely it is: pair it with exploitation evidence before deciding what to patch first.
Is there a patch for CVE-2026-100762?
Yes. A fix has been recorded for CVE-2026-100762. The vendor advisory is the authority on the exact fixed version — apply it from there rather than from a summary.
What does CVE-2026-100762 affect?
CVE-2026-100762 affects Mozilla Firefox < 157, Firefox ESR < 153.4, Firefox ESR < 140.17, Firefox ESR < 115.42. Confirm the exact affected versions against the vendor advisory before deciding you are exposed.
What should I do about CVE-2026-100762?
Update Firefox/ESR to the listed fixed versions immediately.
Exploitation status reflects CISA's KEV catalog as we last synced it. Check the catalog directly.
DOM use-after-free enables sandbox escape from web content, allowing remote code execution as the user and bypassing browser isolation.
Immediate action required