CVE-2026-81433

Fireware OS Pre-Authentication Stack Buffer Overflow in fingerd Allows Remote Code Execution

At a glance

Severity: HIGH 8.7
EPSS: EPSS 0.20 % · percentile 10 (2026-10-27)
State: PUBLISHED
Published: 2026-09-29
Updated: 2026-10-01
Assigner: WatchGuard
NVD status: Deferred

Description

A stack-based buffer overflow vulnerability in WatchGuard Fireware OS's DHCP fingerprinting daemon (fingerd) allows an unauthenticated attacker with adjacent network access to execute arbitrary code or crash the process by sending a specially crafted DHCP packet.

Scores

Version	Score	Vector	Scored by
CVSS 4.0	HIGH 8.7	CVSS:4.0/AV:A/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N	WatchGuard
CVSS 4.0	HIGH 8.7	CVSS:4.0/AV:A/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X	NVD · 5d1c2695-1a31-4499-88ae-e847036fd7e3 (Secondary)

Weaknesses (CWE)

European references

ENISA EUVD · EUVD-2026-89488
GCVE · GCVE-0-2026-81433

Affected products

Product	Versions
WatchGuard · Fireware OS	affected 2026.3 < 2026.3.2 ; affected 2025.0 < 2026.2.3 ; affected 12.0 < 12.12.3

References

https://psirt.watchguard.com/CVE-2026-81433

Sources

Source	Licence
CVE List (CVEProject cvelistV5)	CVE Program Terms of Use
EPSS (FIRST.org)	FIRST — attribution requested
ENISA EUVD	ENISA — reproduction authorised, source acknowledged
NVD (NIST) via fkie-cad/nvd-json-data-feeds	Public domain — this product uses data from the NVD API but is not endorsed or certified by the NVD