High severity · published Jul 2, 2026
CVE-2026-8247
WatchGuard Firebox admd Out of Bounds Write Vulnerability
8.8
CVSS
0.4%
EPSS
No
On KEV
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.
CVSS vector
CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Attack vector
Adjacent
Complexity
Low
Privileges
None
User interaction
None
Confidentiality
High
Integrity
High
Availability
High
Scope
Unchanged
Exploitation
Is it being used?
Exploit prediction (EPSS)0.4% · higher than 32% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
FO
Fireware OS · WatchGuard
2025.1 before 2026.2.1; 12.0 before 12.12.1; 11.0; 12.0 before 12.11.9; 12.0 before 12.5.19 · source: vendor
FI
Fireware · Watchguard
11.0.0 before 11.12.4; 11.12.4; 11.12.4; 12.5 before 12.5.19; 2025.1 before 2026.2.1; 12.0 before 12.12.1 · source: NVD
In the news
VulnerabilityHigh
ZDI-26-428: WatchGuard FireWare OS admd Stack-based Buffer Overflow Remote Code Execution Vulnerability
This vulnerability allows network-adjacent attackers to execute arbitrary code on affected installations of WatchGuard FireWare OS. Authentication is not required to exploit this vulnerability. The ZDI has assigned a CVSS rating of 7.5. The following CVEs are assigned: CVE-2026-8247.
Jul 15, 2026·Zero Day Initiative
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-8247
CVE.org
https://www.cve.org/CVERecord?id=CVE-2026-8247
Broken Link
https://psirt.watchguard.com/CVE-2026-8247
Vendor Advisory
https://www.watchguard.com/wgrd-psirt/advisory/wgsa-2026-00026
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