CVE-2026-81851Network attack vector

Authenticated iked crash via crafted configuration save

Published Aug 27, 2026 · Updated Aug 27, 2026

A heap-based buffer overflow in WatchGuard Fireware OS allows remote authenticated users to crash iked by saving a crafted configuration. The record attributes the overflow to incorrect validation of a specified quantity during configuration saving, but does not name the field or function. Administrator privileges are required, and the documented consequence is interruption of IKE service rather than code execution or data access.

CVSS severity6.9
Medium
EPSS probability0.25%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

A heap-based buffer overflow in WatchGuard Fireware OS allows remote authenticated users to crash iked by saving a crafted configuration. The record attributes the overflow to incorrect validation of a specified quantity during configuration saving, but does not name the field or function. Administrator privileges are required, and the documented consequence is interruption of IKE service rather than code execution or data access.

The record

CVE
CVE-2026-81851
Published
Aug 27, 2026
Updated
Aug 27, 2026
Vendor
WatchGuard Technologies, Inc.
Product
Fireware OS
Classifications
CWE-1284, CWE-122, T1499
Attack vector
network
Privileges
admin

Timeline

How it unfolded

  1. Aug 27, 2026CVE publishedPublication date reported by the CVE source.
  2. Aug 27, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=12.0 <12.11.9
  2. Affected versionversion=12.0 <12.12.1
  3. Affected versionversion=12.0 <12.5.18
  4. Affected versionversion=2025.0 <2026.2.1

What conditions does exploitation require?

Attack vectornetwork
Required privilegesadmin

What is affected?

WatchGuard Technologies, Inc. · Fireware OSversion=12.0 <12.11.9; version=12.0 <12.12.1; version=12.0 <12.5.18; version=2025.0 <2026.2.1

Published CVSS scores

6.9WatchGuardCVSS:4.0/AV:N/AC:L/AT:N/PR:H/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesadmin
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-1284Improper Validation of Specified Quantity in Input
CWE-122Heap-based Buffer Overflow
T1499Endpoint Denial of Service

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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