CVE-2026-86128
Received Received - Intake

NULL Pointer Dereference in Fireware OS NetFlow Packet Processing

Publication date: 2026-09-30

Last updated on: 2026-09-30

Assigner: WatchGuard Technologies, Inc.

Description
A NULL pointer dereference vulnerability in Fireware OS's NetFlow packet-processing feature allows a remote, unauthenticated attacker to cause a denial of service by sending a specially crafted IPv6 packet.

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Meta Information

Published
2026-09-30
Last Modified
2026-09-30
Generated
2026-09-30
AI Q&A
2026-09-30
EPSS Evaluated
N/A
NVD
CVE-2026-86128
EUVD
EUVD-2026-89489

Affected Vendors & Products

Showing 4 associated CPEs
Vendor Product Version / Range
watchguard fireware_os From 2025.0 (inc) to 2026.2.3 (exc)
watchguard fireware_os From 2026.3 (inc) to 2026.3.2 (exc)
watchguard fireware_os From 12.0 (inc) to 12.12.3 (exc)
watchguard fireware_os to 12.5.21 (exc)

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Exploitability

CWE
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KEV
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CWE ID Description
CWE-476 The product dereferences a pointer that it expects to be valid but is NULL.

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Executive Summary

This vulnerability is a NULL pointer dereference flaw in Fireware OS's NetFlow packet-processing feature. It allows a remote attacker to crash the system by sending a specially crafted IPv6 packet without authentication.

Detection Guidance

Detecting this vulnerability requires monitoring for unusual network traffic patterns or crashes in Fireware OS devices. WatchGuard recommends inspecting NetFlow packet processing logs for malformed IPv6 packets. Use network monitoring tools like tcpdump or Wireshark to capture and analyze IPv6 traffic for anomalies targeting NetFlow features.

Impact Analysis

The impact includes denial of service, where the affected system may become unresponsive or crash. This could disrupt network operations and services relying on Fireware OS.

Mitigation Strategies

Immediately update Fireware OS to versions 2026.3.2, 2026.2.3, 12.12.3, or 12.5.21, depending on your current version. If immediate updates are not possible, disable NetFlow packet processing or restrict IPv6 traffic to trusted sources as a temporary workaround.

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