Fireware OS Heap-Based Buffer Overflow in iked Allows Denial of Service (CVE-2026-81851) | HOL Guard CVE

Unknown severity · Source severity not reportedCVE-2026-81851

Fireware OS Heap-Based Buffer Overflow in iked Allows Denial of Service

Answer in brief

CVE-2026-81851 records a Unknown severity vulnerability in Fireware OS Heap-Based Buffer Overflow in iked Allows Denial of Service. The current sources do not mark it as known exploited. The current feed maps WatchGuard/Fireware OS (generic), WatchGuard/Fireware OS (generic), WatchGuard/Fireware OS (generic). Check affected ranges and fixed versions before updating.

Analysis pending evidence review

HOL Guard separates source facts from reviewed analysis. See the methodology.

Published Aug 27, 2026Updated Aug 27, 2026Source checked Aug 28, 2026First seen by HOL Aug 27, 2026Material review Aug 27, 2026

Upstream Advisory

Key facts

Risk: Unknown severitySource severity not reported
Exploitation: Not marked as known exploited
Affected software: 3 mapped packages or products
Fix availability: Available

Why this deserves its current priority

A CVSS score is not reported in the current record. The current sources do not mark it as known exploited. Treat this as a source-backed prioritization signal, not a statement about your environment.

Analysis status

Analysis pending evidence review

Factual feed record only; HOL analysis is not approved for indexing. Read the methodology.

Affected scope and exposure questions

The current feed maps WatchGuard/Fireware OS (generic), WatchGuard/Fireware OS (generic), WatchGuard/Fireware OS (generic). Check affected ranges and fixed versions before updating.

Mapped affected packages and fixed versions
Package	Affected range	Fixed version
WatchGuard/Fireware OSgeneric	>=2025.0 <2026.2.1 \|\| >=12.0 <12.12.1	2026.2.1, 12.12.1
WatchGuard/Fireware OSgeneric	>=12.0 <12.11.9	12.11.9
WatchGuard/Fireware OSgeneric	>=12.0 <12.5.18	12.5.18

Recommended response

Check inventory. Check lockfiles and deployed manifests for WatchGuard/Fireware OS, WatchGuard/Fireware OS, WatchGuard/Fireware OS.
Review the reported fix. Update WatchGuard/Fireware OS to 2026.2.1; WatchGuard/Fireware OS to 12.11.9; WatchGuard/Fireware OS to 12.5.18 if you use the affected versions. Test the change in a non-production environment first.

Evidence timeline and material changes

Published upstream
Aug 27, 2026
Evidence: source:cvelist:source_dates:source-dates:record
Source modified
Aug 27, 2026
Evidence: source:cvelist:source_dates:source-dates:record
First seen by HOL
Aug 27, 2026

Sources and claim methodology

Source referencepsirt.watchguard.com

Upstream source description

A heap-based buffer overflow vulnerability in Fireware OS's iked process allows an authenticated administrator to crash the IKE daemon (iked), resulting in a denial of service, by saving a specially crafted configuration.

Quoted source text, attributed separately from HOL analysis.