CVE-2026-18145 Fireware OS Stack-based Buffer Overflow in spamd Allows Remote Code Execution

What is CVE-2026-18145?

CVE-2026-18145 is a high-severity memory corruption vulnerability in Watchguard Fireware, published on 29 Sep 2026. An attacker needs administrator access to exploit it, with no action from the victim.

Official 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.

Weakness: CWE-121

Which versions are affected by CVE-2026-18145?

It affects 1 product.

Products include Watchguard Fireware.

How do I fix CVE-2026-18145?

No fix has been published for CVE-2026-18145 yet. Limit exposure of the affected software until one is available.

Upgrade to the fixed version. Memory-safe languages, compiler hardening and fuzzing prevent most new cases. More about Memory corruption.

Is CVE-2026-18145 being exploited?

There is no known exploitation of CVE-2026-18145 in the wild and no public exploit code.

Other vulnerabilities in Watchguard Fireware

• CVE-2022-26318 WatchGuard Firebox and XTM Appliances Arbitrary Code Execution Exploited Critical 9.8
• CVE-2025-14733 WatchGuard Firebox Out of Bounds Write Exploited Critical 9.3
• CVE-2025-9242 WatchGuard Firebox Out-of-Bounds Write Exploited Critical 9.3
• CVE-2022-23176 WatchGuard Firebox and XTM Privilege Escalation Exploited High 8.8
• CVE-2022-31789 Integer overflow in n/a Critical 9.8

All Watchguard Fireware vulnerabilities

Sources

• CVE record
• NVD
• OSV
• GitHub advisory
• How this page is made

Also known as GHSA-6g2x-6j83-r28p.