CVE-2026-0884
Use-after-free in Firefox JS engine allows memory corruption.
Is CVE-2026-0884 being exploited?
Not confirmed. CVE-2026-0884 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. EPSS currently estimates a 0.47% probability of exploitation in the next 30 days.
How severe is CVE-2026-0884?
CVE-2026-0884 is rated Critical with a CVSS score of 9.8. 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-2026-0884?
Yes. A fix has been recorded for CVE-2026-0884. The vendor advisory is the authority on the exact fixed version — apply it from there rather than from a summary.
What does CVE-2026-0884 affect?
CVE-2026-0884 affects Mozilla Firefox < 147, Firefox ESR < 140.7. Confirm the exact affected versions against the vendor advisory before deciding you are exposed.
What should I do about CVE-2026-0884?
Upgrade Firefox to the latest version
Exploitation status reflects CISA's KEV catalog as we last synced it. Check the catalog directly.
Remote code execution or browser crash via crafted web content due to JS engine memory corruption.
Immediate action required