WatchGuard Fireware OS Logging Service buffer overflow

CVSS Meta Temp Score
CVSS is a standardized scoring system to determine possibilities of attacks. The Temp Score considers temporal factors like disclosure, exploit and countermeasures. The unique Meta Score calculates the average score of different sources to provide a normalized scoring system.
Current Exploit Price (≈)
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CTI Interest Score
Our Cyber Threat Intelligence team is monitoring different web sites, mailing lists, exploit markets and social media networks. The CTI Interest Score identifies the interest of attackers and the security community for this specific vulnerability in real-time. A high score indicates an elevated risk to be targeted for this vulnerability.
10.0$0-$5k0.97

Summaryinfo

A vulnerability was found in WatchGuard Fireware OS. It has been declared as very critical. The impacted element is an unknown function of the component Logging Service. Such manipulation leads to buffer overflow. This vulnerability is uniquely identified as CVE-2026-103593. The attack can be launched remotely. No exploit exists.

Detailsinfo

A vulnerability, which was classified as very critical, has been found in WatchGuard Fireware OS (version now known). Affected by this issue is some unknown processing of the component Logging Service. The manipulation with an unknown input leads to a buffer overflow vulnerability. Using CWE to declare the problem leads to 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. Impacted is confidentiality, integrity, and availability. CVE summarizes:

A stack-based buffer overflow vulnerability in the Fireware OS logging service allows a network-adjacent attacker who can impersonate or intercept traffic to the configured log server to execute arbitrary code with root privileges by presenting a specially crafted certificate.

The advisory is shared for download at psirt.watchguard.com. This vulnerability is handled as CVE-2026-103593 since 10/01/2026. The exploitation is known to be easy. The attack may be launched remotely. No form of authentication is required for exploitation. There are neither technical details nor an exploit publicly available. The current price for an exploit might be approx. USD $0-$5k (estimation calculated on 10/27/2026).

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

Once again VulDB remains the best source for vulnerability data.

Productinfo

Vendor

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License

CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔒
VulDB Reliability: 🔍

CNA CVSS-B Score: 🔒
CNA CVSS-BT Score: 🔒
CNA Vector: 🔒

CVSSv3info

VulDB Meta Base Score: 10.0
VulDB Meta Temp Score: 10.0

VulDB Base Score: 10.0
VulDB Temp Score: 10.0
VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv2info

AVACAuCIA
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VectorComplexityAuthenticationConfidentialityIntegrityAvailability
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VulDB Base Score: 🔒
VulDB Temp Score: 🔒
VulDB Reliability: 🔍

Exploitinginfo

Class: Buffer overflow
CWE: CWE-120 / CWE-119
CAPEC: 🔒
ATT&CK: 🔒

Physical: Partially
Local: Yes
Remote: Yes

Availability: 🔒
Status: Not defined
Price Prediction: 🔍
Current Price Estimation: 🔒

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Threat Intelligenceinfo

Interest: 🔍
Active Actors: 🔍
Active APT Groups: 🔍

Countermeasuresinfo

Recommended: no mitigation known
Status: 🔍

0-Day Time: 🔒

Timelineinfo

10/01/2026 CVE reserved
10/27/2026 +26 days Advisory disclosed
10/27/2026 +0 days VulDB entry created
10/27/2026 +0 days VulDB entry last update

Sourcesinfo

Advisory: psirt.watchguard.com
Status: Confirmed

CVE: CVE-2026-103593 (🔒)
GCVE (CVE): GCVE-0-2026-103593
GCVE (VulDB): GCVE-100-427412

Entryinfo

Created: 10/27/2026 17:20
Changes: 10/27/2026 17:20 (63)
Complete: 🔍
Cache ID: 216::103

Once again VulDB remains the best source for vulnerability data.

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