CVE-2026-18145
Received Received - Intake

Stack-Based Buffer Overflow in WatchGuard Fireware OS SpamBlocker Service

Publication date: 2026-09-30

Last updated on: 2026-09-30

Assigner: WatchGuard Technologies, Inc.

Description
A stack-based buffer overflow vulnerability in the spamBlocker (spamd) service of WatchGuard Fireware OS allows an authenticated attacker with administrator privileges to crash the service or potentially execute arbitrary code by sending a specially crafted management request.

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Meta Information

Published
2026-09-30
Last Modified
2026-09-30
Generated
2026-09-30
AI Q&A
2026-09-30
EPSS Evaluated
N/A
NVD
CVE-2026-18145
EUVD
EUVD-2026-89500

Affected Vendors & Products

Showing 3 associated CPEs
Vendor Product Version / Range
watchguard fireware_os From 2025.0 (inc) to 2026.3.2 (inc)
watchguard fireware_os From 12.0 (inc) to 12.12.3 (inc)
watchguard fireware_os From 12.0 (inc) to 12.5.21 (inc)

Helpful Resources

Exploitability

CWE
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KEV
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CWE ID Description
CWE-121 A stack-based buffer overflow condition is a condition where the buffer being overwritten is allocated on the stack (i.e., is a local variable or, rarely, a parameter to a function).

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Executive Summary

This is a stack-based buffer overflow vulnerability in WatchGuard Fireware OS's spamBlocker (spamd) service. An authenticated attacker with admin privileges can send a specially crafted management request to crash the service or potentially execute arbitrary code.

Detection Guidance

To detect this vulnerability, monitor the spamBlocker (spamd) service for crashes or unusual behavior. Check Fireware OS versions against affected ranges (2026.3-2026.3.2, 2025.0-2026.2.3, 12.0-12.12.3, T15/T35 12.0-12.5.21). Use system logs to identify crashes in spamd or management request anomalies.

Impact Analysis

An attacker could exploit this to crash the spamBlocker service, disrupting email filtering and potentially gaining control over the affected system. This requires admin access but could lead to service disruption or unauthorized code execution.

Compliance Impact

This vulnerability could potentially impact compliance with GDPR and HIPAA by allowing unauthorized code execution or service disruption if exploited. An attacker with admin privileges could crash the spamBlocker service or run arbitrary code, which may lead to unauthorized data access, processing disruptions, or data integrity issues. Such incidents could violate GDPR's security principles or HIPAA's integrity and availability requirements.

Mitigation Strategies

Immediately update Fireware OS to patched versions (2026.3.2, 2026.2.3, 12.12.3, 12.5.21). Restrict administrative access to trusted users only. Disable the spamBlocker service if not required. Monitor for exploitation attempts via network traffic analysis.

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