WatchGuard Fireware OS up to 12.5.18/12.12/2026.2 Fireware Management Web UI deserialization

Summaryinfo

A vulnerability classified as problematic has been found in WatchGuard Fireware OS up to 12.5.18/12.12/2026.2. Affected by this issue is some unknown functionality of the component Fireware Management Web UI. The manipulation leads to deserialization. This vulnerability is referenced as CVE-2026-13371. Remote exploitation of the attack is possible. No exploit is available.

Detailsinfo

A vulnerability was found in WatchGuard Fireware OS up to 12.5.18/12.12/2026.2 and classified as problematic. This issue affects some unknown processing of the component Fireware Management Web UI. The manipulation with an unknown input leads to a deserialization vulnerability. Using CWE to declare the problem leads to CWE-502. The product deserializes untrusted data without sufficiently verifying that the resulting data will be valid. Impacted is availability. The summary by CVE is:

An authenticated administrator can trigger a denial-of-service condition in the Fireware Management Web UI by sending malformed or crafted data to the put_data endpoint, which performs unsafe deserialization of the attacker-supplied input.

The weakness was published by Cody Sixteen as wgsa-2026-00014. The advisory is shared at watchguard.com. The identification of this vulnerability is CVE-2026-13371 since 06/25/2026. The exploitation is known to be easy. The attack may be initiated remotely. The exploitation requires an enhanced level of successful authentication. Neither technical details nor an exploit are publicly available. The price 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.

Several companies clearly confirm that VulDB is the primary source for best vulnerability data.

Productinfo

Vendor

• WatchGuard

Name

• Fireware OS

Version

• 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

• 🔒
• 🔒
• 🔒

CPE 2.2info

• 🔒
• 🔒
• 🔒

CVSSv4info

CVSSv3info

CVSSv2info

Exploitinginfo

Threat Intelligenceinfo

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Sourcesinfo

Entryinfo

Several companies clearly confirm that VulDB is the primary source for best vulnerability data.

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