CVE-2026-93866

Fireware OS Pre-Authentication Integer Overflow in Access Portal Allows Out-of-Bounds Write

State: Published
Severity: 9.2 Critical
Published: Oct 27, 2026
Updated: Oct 27, 2026
Reserved: Sep 18, 2026

Description

An integer overflow vulnerability in the WebSocket connection handling used by WatchGuard Fireware OS's Access Portal allows a remote, unauthenticated attacker to write beyond the bounds of a heap buffer by sending a specially crafted request while the Access Portal feature is enabled.

Scores

CVSS	Score	Vector	Source
4.0	9.2 Critical	CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N	WatchGuard

Weaknesses

Affected Products

Product	Versions
Fireware OSWatchGuard	2025.1 to before 2026.4Affected 12.0 to before 12.12.4Affected
Fireware OSWatchGuard	12.0 to before 12.5.22Affected

References

https://psirt.watchguard.com/CVE-2026-93866vendor-advisory

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