Is CVE-2026-112709 exploited in the wild?

No. Junglewise Threat Intelligence has no report of CVE-2026-112709 being exploited in the wild.

How severe is CVE-2026-112709?

Informational severity, published 27 October 2026.

Which products and versions are affected?

Watchguard Fireware OS Default line >= 2025.1, = 12.0, = 12.0, < 12.12.4.

Is there a fix for CVE-2026-112709?

Yes: fixed in Fireware OS 2026.4, Fireware OS 12.12.4, Fireware OS 12.5.22. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

How is CVE-2026-112709 attacked?

It is attacked over the network, in a network appliance.

Am I affected by CVE-2026-112709?

Check whether you run Watchguard Fireware OS at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

CVE-2026-112709: WatchGuard Fireware OS heap buffer overflow in AD authentication

Q: Is there a fix for CVE-2026-112709?

Yes: fixed in Fireware OS 2026.4, Fireware OS 12.12.4, Fireware OS 12.5.22. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

Q: How is CVE-2026-112709 attacked?

It is attacked over the network, in a network appliance.

Q: Am I affected by CVE-2026-112709?

Check whether you run Watchguard Fireware OS at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

CVE-2026-112709 · Severity: info · Published 2026-10-27

WatchGuard Fireware OS is a firewall operating system that protects networks and secures connections to directory services like Active Directory. A heap buffer overflow in its authentication service allows an attacker who intercepts traffic to the Active Directory server to crash the firewall or execute arbitrary code without authentication. Affected deployments rely on Active Directory for user authentication.

Technologies: Watchguard Fireware OS. Vendors: Watchguard.

Quick answers

Is CVE-2026-112709 exploited in the wild?: No. Junglewise Threat Intelligence has no report of CVE-2026-112709 being exploited in the wild.
How severe is CVE-2026-112709?: Informational severity, published 27 October 2026.
Which products and versions are affected?: Watchguard Fireware OS Default line >= 2025.1, < 2026.4; T15/T35 >= 12.0, < 12.5.22; T series >= 12.0, < 12.12.4.
Is there a fix for CVE-2026-112709?: Yes: fixed in Fireware OS 2026.4, Fireware OS 12.12.4, Fireware OS 12.5.22. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.
How is CVE-2026-112709 attacked?: It is attacked over the network, in a network appliance.
Am I affected by CVE-2026-112709?: Check whether you run Watchguard Fireware OS at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

How to fix

Fixed in: Fireware OS 2026.4, Fireware OS 12.12.4, Fireware OS 12.5.22

Technical details

A heap-based buffer overflow (CWE-122, CWE-131, CWE-787) in Fireware OS's authentication service is triggered when the service processes a specially crafted response from an Active Directory server. An attacker who controls or intercepts traffic to the configured AD server can exploit this pre-authentication to cause denial of service or achieve remote code execution. No mitigation short of upgrade is documented.

Affected products

WatchGuard Fireware OS Default line >= 2025.1, < 2026.4; T15/T35 >= 12.0, < 12.5.22; T series >= 12.0, < 12.12.4

Timeline

2026-10-27: disclosed

References

https://psirt.watchguard.com/CVE-2026-112709

This page as Markdown. Free to reuse under CC BY 4.0 with a link back.