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major vulnerability· requires attention

Remote RCE as root on WatchGuard Firebox firewalls via BOVPN TLS client; compromises perimeter devices, high CVSS, widespread operational impact across organizations.

Networks

CVE-2026-86131

9.2
Critical
EPSS n/aSep 30, 2026

Remote root RCE via BOVPN Over TLS client in WatchGuard Fireware

common questions

Is CVE-2026-86131 being exploited?

Not confirmed. CVE-2026-86131 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-2026-86131?

CVE-2026-86131 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-2026-86131?

Not known from our data. No patch reference has been recorded for CVE-2026-86131, 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-2026-86131 affect?

CVE-2026-86131 affects WatchGuard Firebox (Fireware OS BOVPN Over TLS client), Fireware OS-based appliances. Confirm the exact affected versions against the vendor advisory before deciding you are exposed.

What should I do about CVE-2026-86131?

Block untrusted BOVPN TLS peers; restrict VPN endpoints; apply vendor patch when available.

Exploitation status reflects CISA's KEV catalog as we last synced it. Check the catalog directly.

executive summary
technical analysis
affected
WatchGuard Firebox (Fireware OS BOVPN Over TLS client)Fireware OS-based appliances
impact

Remote attacker controlling a VPN server can execute arbitrary commands as root on Firebox, enabling full firewall compromise and network breach.

action required

Immediate action required

affected versions
WatchGuard Fireware OS
  • affected>= 2026.3 and < 2026.3.2
  • affected>= 2025.0 and < 2026.2.3
  • affected>= 12.0 and < 12.12.3
  • affected>= 12.0 and < 12.5.21

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.

how to fix
Remediation steps are tailored for users whose stack is affected. Add this technology to your stack to see the fix checklist.
references
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