by Kastro
Paper/Archive/CVE-2026-93866

CVE-2026-93866

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

EPSS 0.4%CVSS 9.2
critical.is priorityof 100
35
CVSS 9.2 (CNA)9.2 / 10 × 3027.6Not in CISA KEV+300.0EPSS percentile 38.9.389 × 207.8No public exploit+100.0SSVC exploitation: unknown+100.0
Description · from the CVE record

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.

Affected

ProductAffectedFixed inSource
Fireware OS2025.1 – < 2026.42026.4CNA
Fireware OS12.0 – < 12.12.412.12.4CNA
Fireware OS12.0 – < 12.5.2212.5.22CNA

Scores by source

WatchGuard (CNA)9.2CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N

References

advisorypsirt.watchguard.com/CVE-2026-93866