Is CVE-2026-93857 exploited in the wild?

No. Junglewise Threat Intelligence has no report of CVE-2026-93857 being exploited in the wild.

How severe is CVE-2026-93857?

Informational severity, published 27 October 2026.

Which products and versions are affected?

Watchguard Fireware OS 2026.x before 2026.4; 12.x before 12.12.4; 12.5.x before 12.5.22.

How is CVE-2026-93857 attacked?

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

Am I affected by CVE-2026-93857?

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-2026-93857: WatchGuard Fireware OS stack buffer overflow in SIP proxy

CVE-2026-93857 · Severity: info · Published 2026-10-27

Fireware OS is network security software that manages firewalls and gateways. A stack buffer overflow in its SIP proxy component allows an attacker on the network to execute arbitrary code without authentication by sending a specially crafted SIP request, potentially giving them complete control of the device.

Technologies: Watchguard Fireware OS. Vendors: Watchguard.

Quick answers

Is CVE-2026-93857 exploited in the wild?: No. Junglewise Threat Intelligence has no report of CVE-2026-93857 being exploited in the wild.
How severe is CVE-2026-93857?: Informational severity, published 27 October 2026.
Which products and versions are affected?: Watchguard Fireware OS 2026.x before 2026.4; 12.x before 12.12.4; 12.5.x before 12.5.22.
Is there a fix for CVE-2026-93857?: Yes: fixed in Fireware OS 2026.4, Fireware OS 12.12.4, Fireware OS 12.5.22. Until then: Disable the SIP proxy if not required, or restrict network access to SIP traffic only from trusted sources until the device can be patched. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.
How is CVE-2026-93857 attacked?: It is attacked over the network, in a network appliance.
Am I affected by CVE-2026-93857?: 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

Disable the SIP proxy if not required, or restrict network access to SIP traffic only from trusted sources until the device can be patched.

Technical details

A stack-based buffer overflow (CWE-121, CWE-120) in the SIP proxy component of Fireware OS allows remote, unauthenticated code execution via malformed SIP requests. Exploitation requires the SIP proxy to be configured and enabled on the Firebox device. The vulnerability is fixed in Fireware OS versions 2026.4, 12.12.4, and 12.5.22.

Affected products

WatchGuard Fireware OS 2026.x before 2026.4; 12.x before 12.12.4; 12.5.x before 12.5.22

Timeline

2026-10-27: disclosed
2026-10-27: patched

References

https://psirt.watchguard.com/CVE-2026-93857

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