CVE-2026-86131: A code injection vulnerability in WatchGuard Fireware OS's BOVPN Over TLS client configuration handling allows

Q: How do I fix CVE-2026-86131?

fireware: upgrade to 12.5.21, 12.12.3, 2026.2.3, 2026.3.2. Exact commands for each OS are on this page.

Q: Is CVE-2026-86131 being exploited?

CVE-2026-86131 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

Q: What does CVE-2026-86131 affect?

CVE-2026-86131 affects fireware. Severity is critical (CVSS 9.8). A code injection vulnerability in WatchGuard Fireware OS's BOVPN Over TLS client configuration handling allows an attacker who controls the remote VPN server to execute arbitrary commands as root on the connecting Firebox.

Q: How urgent is CVE-2026-86131?

Priority 49/100. Critical severity; Remotely exploitable, no login, no user action

This month

CRITICAL 9.8REMOTEUPGRADE

CVE-2026-86131 is a critical-severity flaw (CVSS 9.8) affecting fireware. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

A code injection vulnerability in WatchGuard Fireware OS's BOVPN Over TLS client configuration handling allows an attacker who controls the remote VPN server to execute arbitrary commands as root on the connecting Firebox.

Why this priority

Critical severity
Remotely exploitable, no login, no user action

A fixed release or distro patch exists.

Risk facts

CVSS score	9.8 (Critical)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	None
User interaction	None
EPSS exploit chance	0.5% (top 60%)
CISA exploited list	No
Weakness	CWE-94, CWE-295, CWE-829
Published	2026-09-30
Last modified	2026-10-06

Publisher (CNA): WatchGuard Technologies, Inc. · Vendor: watchguard

Last updated 2026-10-06 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2026-09-30 00:16 UTCPublished CVE record published
2026-10-06 20:39 UTCUpdated Record last modified

watchguard fireware UPGRADE

Affected: >= 12.0 and < 12.5.21 · >= 12.12 and < 12.12.3 · >= 2025.0 and < 2026.2.3 · >= 2026.3 and < 2026.3.2

Fixed in: 12.5.21, 12.12.3, 2026.2.3, 2026.3.2

Safe to downgrade to: a release before 12.0

Check your OS release

cat /etc/os-release; uname -r

Debian / Ubuntu

sudo apt update && sudo apt full-upgrade

RHEL / Amazon Linux / Fedora

sudo dnf upgrade --refresh

Windows

Install the latest cumulative update from Windows Update

If no patch exists yet

OS downgrades are not safe. Apply the vendor mitigation from the advisory and restrict exposure.

Verify at the official source NVD · CVE Program · Report a problem with this page
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.

Quick answers

How do I fix CVE-2026-86131?

fireware: upgrade to 12.5.21, 12.12.3, 2026.2.3, 2026.3.2. Exact commands for each OS are on this page.

Is CVE-2026-86131 being exploited?

CVE-2026-86131 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

What does CVE-2026-86131 affect?

CVE-2026-86131 affects fireware. Severity is critical (CVSS 9.8). A code injection vulnerability in WatchGuard Fireware OS's BOVPN Over TLS client configuration handling allows an attacker who controls the remote VPN server to execute arbitrary commands as root on the connecting Firebox.

How urgent is CVE-2026-86131?

Priority 49/100. Critical severity; Remotely exploitable, no login, no user action

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References

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