Unauthenticated remote code execution in a widely deployed firewall OS (perimeter device). Exploitation can fully compromise firewalls and enable network pivoting — organization-wide impact.
CVE-2026-93857
Unauthenticated RCE in Fireware OS SIP proxy via crafted SIP requests
Is CVE-2026-93857 being exploited?
Not confirmed. CVE-2026-93857 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-2026-93857?
CVE-2026-93857 is rated Critical with a CVSS score of 9.2. 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-2026-93857?
Not known from our data. No patch reference has been recorded for CVE-2026-93857, which is not the same as no patch existing — a fix may have shipped without a tagged reference, or after this record was written. The vendor advisory is the only authority on whether a fix exists, and mitigations may be available regardless.
What does CVE-2026-93857 affect?
CVE-2026-93857 affects WatchGuard Fireware OS, WatchGuard Firebox appliances, Any policy using the SIP proxy. Confirm the exact affected versions against the vendor advisory before deciding you are exposed.
What should I do about CVE-2026-93857?
Disable/restrict SIP proxy, block SIP from untrusted networks, monitor logs, apply vendor patch when released.
Exploitation status reflects CISA's KEV catalog as we last synced it. Check the catalog directly.
Unauthenticated remote code execution on firewall (full system compromise), persistent backdoor, lateral movement, and traffic interception.
Immediate action required
- affected>= 2025.1 and < 2026.4
- affected>= 12.0 and < 12.12.4
- affected>= 12.0 and < 12.5.22
As published in the CVE Program record. A version outside these ranges is not a statement that it is unaffected — vendors sometimes understate a range, and distribution-backported builds carry upstream numbers that do not reflect what was patched into them.