NULL Pointer Dereference Vulnerability in Fireware OS by WatchGuard
CVE-2026-86128

8.2HIGH

Key Information:

Vendor

Watchguard

Status
Fireware Os
Vendor
CVE Published:
29 September 2026

Badges

👾 Exploit Exists

What is CVE-2026-86128?

A vulnerability in WatchGuard's Fireware OS within the NetFlow packet-processing feature can be exploited by a remote, unauthenticated attacker. By crafting and sending a specific IPv6 packet, the attacker can trigger a NULL pointer dereference, resulting in a denial of service. This issue can lead to unavailability of the affected systems, highlighting the necessity for immediate security measures and patches.

Affected Version(s)

Fireware OS Default 2026.3 < 2026.3.2

Fireware OS Default 2025.0 < 2026.2.3

Fireware OS Default 12.0 < 12.12.3

References

https://psirt.watchguard.com/CVE-2026-86128
vendor-advisory

CVSS V4

Score:
8.2
Severity:
HIGH
Confidentiality:
None
Integrity:
None
Availability:
High
Attack Vector:
Network
Attack Complexity:
Low
Attack Required:
Physical
Privileges Required:
Undefined
User Interaction:
None

Timeline

  • 👾

    Exploit known to exist

  • Vulnerability published

  • Vulnerability Reserved

Credit

WatchGuard AI Security Research
.