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7.7
HIGH CVSS 4.0
CVE-2026-8247
WatchGuard Firebox admd Out of Bounds Write Vulnerability
Overview
Description

An Out-of-bounds Write vulnerability in WatchGuard Fireware OS may allow an unauthenticated attacker on the same local network segment to execute arbitrary code. This vulnerability affects Fireware OS 11.0 up to and including 11.12.4_Update1, 12.0 up to and including 12.12 and 2025.1 up to and including 2026.2.

Details
INFO

Published Date :

July 3, 2026, 12:16 a.m.

Last Modified :

July 7, 2026, 5:16 a.m.

Remotely Exploit :

No

Source :

5d1c2695-1a31-4499-88ae-e847036fd7e3
Impact
Affected Products

The following products are affected by CVE-2026-8247 vulnerability. Even if cvefeed.io is aware of the exact versions of the products that are affected, the information is not represented in the table below.

ID Vendor Product Action
1 Watchguard fireware_os
: Total Affected Vendor : 1 | Products : 1
Scoring
CVSS Scores
The Common Vulnerability Scoring System is a standardized framework for assessing the severity of vulnerabilities in software and systems. We collect and displays CVSS scores from various sources for each CVE.
Score Version Severity Vector Exploitability Score Impact Score Source
CVSS 134c704f-9b21-4f2e-91b3-4a467353bcc0
CVSS 4.0 HIGH 5d1c2695-1a31-4499-88ae-e847036fd7e3
CVSS 4.0 HIGH 5d1c2695-1a31-4499-88ae-e847036fd7e3
Solution
Apply vendor patches to fix an out-of-bounds write vulnerability and prevent arbitrary code execution.
  • Update Fireware OS to the latest vendor-provided version.
  • Apply all available security patches from the vendor.
  • Verify system is running a patched version.
References
References to Advisories, Solutions, and Tools

Here, you will find a curated list of external links that provide in-depth information, practical solutions, and valuable tools related to CVE-2026-8247.

URL Resource
https://www.watchguard.com/wgrd-psirt/advisory/wgsa-2026-00026
CWE - Common Weakness Enumeration

While CVE identifies specific instances of vulnerabilities, CWE categorizes the common flaws or weaknesses that can lead to vulnerabilities. CVE-2026-8247 is associated with the following CWEs:

Common Attack Pattern Enumeration and Classification (CAPEC)

Common Attack Pattern Enumeration and Classification (CAPEC) stores attack patterns, which are descriptions of the common attributes and approaches employed by adversaries to exploit the CVE-2026-8247 weaknesses.

CAPEC-8: Buffer Overflow in an API Call Buffer Overflow in an API Call CAPEC-9: Buffer Overflow in Local Command-Line Utilities Buffer Overflow in Local Command-Line Utilities CAPEC-10: Buffer Overflow via Environment Variables Buffer Overflow via Environment Variables CAPEC-14: Client-side Injection-induced Buffer Overflow Client-side Injection-induced Buffer Overflow CAPEC-24: Filter Failure through Buffer Overflow Filter Failure through Buffer Overflow CAPEC-42: MIME Conversion MIME Conversion CAPEC-44: Overflow Binary Resource File Overflow Binary Resource File CAPEC-45: Buffer Overflow via Symbolic Links Buffer Overflow via Symbolic Links CAPEC-46: Overflow Variables and Tags Overflow Variables and Tags CAPEC-47: Buffer Overflow via Parameter Expansion Buffer Overflow via Parameter Expansion CAPEC-67: String Format Overflow in syslog() String Format Overflow in syslog() CAPEC-92: Forced Integer Overflow Forced Integer Overflow CAPEC-100: Overflow Buffers Overflow Buffers

We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).

Results are limited to the first 15 repositories due to potential performance issues.

The following list is the news that have been mention CVE-2026-8247 vulnerability anywhere in the article.

Results are limited to the first 20 news articles due to potential performance issues.

The following table lists the changes that have been made to the CVE-2026-8247 vulnerability over time.

Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.

  • CVE Modified by 134c704f-9b21-4f2e-91b3-4a467353bcc0

    Jul. 07, 2026

    Action Type Old Value New Value
    Changed SSVC {'id': 'CVE-2026-8247', 'role': 'CISA Coordinator', 'options': [{'exploitation': 'none'}, {'automatable': 'no'}, {'technicalImpact': 'total'}], 'version': '2.0.3', 'timestamp': '2026-07-06T15:46:50.741660Z'} {'id': 'CVE-2026-8247', 'role': 'CISA Coordinator', 'options': [{'exploitation': 'none'}, {'automatable': 'no'}, {'technicalImpact': 'total'}], 'version': '2.0.3', 'timestamp': '2026-07-06T00:00:00+00:00'}
  • CVE Modified by 134c704f-9b21-4f2e-91b3-4a467353bcc0

    Jul. 06, 2026

    Action Type Old Value New Value
    Added SSVC {'id': 'CVE-2026-8247', 'role': 'CISA Coordinator', 'options': [{'exploitation': 'none'}, {'automatable': 'no'}, {'technicalImpact': 'total'}], 'version': '2.0.3', 'timestamp': '2026-07-06T15:46:50.741660Z'}
  • New CVE Received by 5d1c2695-1a31-4499-88ae-e847036fd7e3

    Jul. 03, 2026

    Action Type Old Value New Value
    Added Affected [{'vendor': 'WatchGuard', 'product': 'Fireware OS', 'versions': [{'status': 'affected', 'version': '11.0', 'versionType': 'semver', 'lessThanOrEqual': '11.12.4+541730'}, {'status': 'affected', 'version': '12.0', 'versionType': 'semver', 'lessThanOrEqual': '12.12'}, {'status': 'affected', 'version': '12.5', 'versionType': 'semver', 'lessThanOrEqual': '12.5.18'}, {'status': 'affected', 'version': '2025.1', 'versionType': 'semver', 'lessThanOrEqual': '2026.2'}], 'defaultStatus': 'unaffected'}]
    Added Description An Out-of-bounds Write vulnerability in WatchGuard Fireware OS may allow an unauthenticated attacker on the same local network segment to execute arbitrary code. This vulnerability affects Fireware OS 11.0 up to and including 11.12.4_Update1, 12.0 up to and including 12.12 and 2025.1 up to and including 2026.2.
    Added CVSS V4.0 AV:A/AC:L/AT:P/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
    Added CWE CWE-120
    Added Reference https://www.watchguard.com/wgrd-psirt/advisory/wgsa-2026-00026
EPSS is a daily estimate of the probability of exploitation activity being observed over the next 30 days. Following chart shows the EPSS score history of the vulnerability.
CVSS
Vulnerability Scoring Details
Base CVSS Score: 7.7
Attack Vector
Attack Complexity
Attack Requirements
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