High-severity RCE from memory-corruption in widely deployed Firefox ESR; enterprise clients commonly use ESR and remote compromise via web content can disrupt organizations.
CVE-2026-16361
Memory-corruption RCE in Firefox ESR enabling arbitrary code execution via web content
Is CVE-2026-16361 being exploited?
Not confirmed. CVE-2026-16361 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 0.32% probability of exploitation in the next 30 days.
How severe is CVE-2026-16361?
CVE-2026-16361 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-2026-16361?
Yes. A fix has been recorded for CVE-2026-16361. The vendor advisory is the authority on the exact fixed version — apply it from there rather than from a summary.
What does CVE-2026-16361 affect?
CVE-2026-16361 affects Firefox ESR 115.37, Firefox ESR 140.12, Desktop (Windows/macOS/Linux). Confirm the exact affected versions against the vendor advisory before deciding you are exposed.
What should I do about CVE-2026-16361?
Update ESR to 115.38 or 140.13 immediately; block or isolate unpatched clients until patched.
Exploitation status reflects CISA's KEV catalog as we last synced it. Check the catalog directly.
Remote code execution via memory corruption when processing crafted web content; attacker can run arbitrary code as the user.
Immediate action required