CVE-2026-16359
Boundary-check flaw in Firefox GMP enabling remote code execution via media.
Is CVE-2026-16359 being exploited?
Not confirmed. CVE-2026-16359 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 0.26% probability of exploitation in the next 30 days.
How severe is CVE-2026-16359?
CVE-2026-16359 is rated Critical with a CVSS score of 9.1. 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-2026-16359?
Yes. A fix has been recorded for CVE-2026-16359. The vendor advisory is the authority on the exact fixed version — apply it from there rather than from a summary.
What does CVE-2026-16359 affect?
CVE-2026-16359 affects Mozilla Firefox (desktop) versions before 153, Firefox ESR versions before 115.38, Firefox ESR 140 versions before 140.13. Confirm the exact affected versions against the vendor advisory before deciding you are exposed.
What should I do about CVE-2026-16359?
Update Firefox to 153 or ESR 115.38 / 140.13+ immediately
Exploitation status reflects CISA's KEV catalog as we last synced it. Check the catalog directly.
Crafted media can trigger memory corruption leading to remote code execution as the user or renderer process.
Immediate action required