WatchGuard Fireware OS up to 11.12.4+541730/12.5.18/12.12/2026.2 buffer overflow

Summaryinfo

A vulnerability classified as critical has been found in WatchGuard Fireware OS up to 11.12.4+541730/12.5.18/12.12/2026.2. This issue affects some unknown processing. This manipulation causes buffer overflow. The identification of this vulnerability is CVE-2026-8247. The attack needs to be done within the local network. There is no exploit available.

Detailsinfo

A vulnerability classified as critical was found in WatchGuard Fireware OS up to 11.12.4+541730/12.5.18/12.12/2026.2. Affected by this vulnerability is some unknown processing. The manipulation with an unknown input leads to a buffer overflow vulnerability. The CWE definition for the vulnerability is CWE-120. The product copies an input buffer to an output buffer without verifying that the size of the input buffer is less than the size of the output buffer, leading to a buffer overflow. As an impact it is known to affect confidentiality, integrity, and availability. The summary by CVE is:

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.

The weakness was shared by Xander Mackenzie as wgsa-2026-00026. It is possible to read the advisory at watchguard.com. This vulnerability is known as CVE-2026-8247 since 05/10/2026. The exploitation appears to be easy. Access to the local network is required for this attack to succeed. The exploitation doesn't need any form of authentication. The technical details are unknown and an exploit is not publicly available. The pricing for an exploit might be around USD $0-$5k at the moment (estimation calculated on 07/03/2026).

There is no information about possible countermeasures known. It may be suggested to replace the affected object with an alternative product.

Be aware that VulDB is the high quality source for vulnerability data.

Productinfo

Vendor

• WatchGuard

Name

• Fireware OS

Version

• 11.12.4+541730
• 12.0
• 12.1
• 12.2
• 12.3
• 12.4
• 12.5
• 12.5.0
• 12.5.1
• 12.5.2
• 12.5.3
• 12.5.4
• 12.5.5
• 12.5.6
• 12.5.7
• 12.5.8
• 12.5.9
• 12.5.10
• 12.5.11
• 12.5.12
• 12.5.13
• 12.5.14
• 12.5.15
• 12.5.16
• 12.5.17
• 12.5.18
• 12.6
• 12.7
• 12.8
• 12.9
• 12.10
• 12.11
• 12.12
• 2026.0
• 2026.1
• 2026.2

License

• commercial

CPE 2.3info

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CPE 2.2info

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Entryinfo

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