CVE-2026-8247 | WatchGuard Firebox admd Out of Bounds Write Vulnerability

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.

Published: 2026-07-02 Last update: 2026-07-02 Assigner: 5d1c2695-1a31-4499-88ae-e847036fd7e3 Source: 5d1c2695-1a31-4499-88ae-e847036fd7e3
NVD Status：Received，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2026-8247 is rated Low Risk (34.3/100): CVSS High severity, with low exploitation likelihood (EPSS 0.20%). Monitor for updates and reassess as exploit intelligence or EPSS changes.

Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.

Exploit prediction scoring system (EPSS) score for CVE-2026-8247

EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).

# Date Old EPSS score New EPSS score Delta (New - Old)
1 2026-07-04 — 0.20% —

Full EPSS history (1 record total)

Common vulnerability scoring system (CVSS) metrics for CVE-2026-8247

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
7.7 4.0 HIGH
CVSS:4.0/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 Click to expand
Attack vector (AV:A)
Attacker has to be on an adjacent/local network segment.
Attack complexity (AC:L)
Exploitation conditions are straightforward and stable.
Attack requirements (AT:P)
Additional preconditions must be present for exploitation.
Privileges required (PR:N)
No privileges are required.
User interaction (UI:N)
No user interaction is required.
Vulnerable system confidentiality impact (VC:H)
High confidentiality impact on the vulnerable system.
Vulnerable system integrity impact (VI:H)
High integrity impact on the vulnerable system.
Vulnerable system availability impact (VA:H)
High availability impact on the vulnerable system.
Subsequent system confidentiality impact (SC:N)
No confidentiality impact on subsequent systems.
Subsequent system integrity impact (SI:N)
No integrity impact on subsequent systems.
Subsequent system availability impact (SA:N)
No availability impact on subsequent systems.
Exploit maturity (threat) (E:X)
Not defined: no reliable threat intelligence; scoring assumes the worst case (equivalent to Attacked).
Confidentiality requirement (CR:X)
Not defined: insufficient information; scoring treats this like High (worst case).
Integrity requirement (IR:X)
Not defined: insufficient information; scoring treats this like High (worst case).
Availability requirement (AR:X)
Not defined: insufficient information; scoring treats this like High (worst case).
Modified attack vector (MAV:X)
Not defined: scoring uses the Base Attack Vector (AV).
Modified attack complexity (MAC:X)
Not defined: scoring uses the Base Attack Complexity (AC).
Modified attack requirements (MAT:X)
Not defined: scoring uses the Base Attack Requirements (AT).
Modified privileges required (MPR:X)
Not defined: scoring uses the Base Privileges Required (PR).
Modified user interaction (MUI:X)
Not defined: scoring uses the Base User Interaction (UI).
Modified vulnerable system confidentiality impact (MVC:X)
Not defined: scoring uses the Base VC metric.
Modified vulnerable system integrity impact (MVI:X)
Not defined: scoring uses the Base VI metric.
Modified vulnerable system availability impact (MVA:X)
Not defined: scoring uses the Base VA metric.
Modified subsequent system confidentiality impact (MSC:X)
Not defined: scoring uses the Base SC metric.
Modified subsequent system integrity impact (MSI:X)
Not defined: scoring uses the Base SI metric.
Modified subsequent system availability impact (MSA:X)
Not defined: scoring uses the Base SA metric.
Safety (supplemental) (S:X)
Not evaluated.
Automatable (supplemental) (AU:X)
Not evaluated.
Recovery (supplemental) (R:X)
Not evaluated.
Value density (supplemental) (V:X)
Not evaluated.
Vulnerability response effort (supplemental) (RE:X)
Not evaluated.
Provider urgency (supplemental) (U:X)
Not evaluated.
 — — 5d1c2695-1a31-4499-88ae-e847036fd7e3

Weakness enumeration for CVE-2026-8247

GitHub Security Advisory for CVE-2026-8247

GHSA-h2w9-p676-66ch · Severity: high — An Out-of-bounds Write vulnerability in WatchGuard Fireware OS may allow an unauthenticated...

Affected software / configurations for CVE-2026-8247

Vendor Product Version Raw CPE
watchguard fireware_os >= 11.0, <= 11.12.4+541730 cpe:2.3:a:watchguard:fireware_os:*:*:*:*:*:*:*:11.0
watchguard fireware_os >= 12.0, <= 12.12 cpe:2.3:a:watchguard:fireware_os:*:*:*:*:*:*:*:12.0
watchguard fireware_os >= 12.5, <= 12.5.18 cpe:2.3:a:watchguard:fireware_os:*:*:*:*:*:*:*:12.5
watchguard fireware_os >= 2025.1, <= 2026.2 cpe:2.3:a:watchguard:fireware_os:*:*:*:*:*:*:*:2025.1

References for CVE-2026-8247

cvelogic Threat Intelligence