High

Stack-based Buffer Overflow in WatchGuard Agent Discovery Service on Windows

IdentifiersCVE-2026-41287CWE-121· Stack-based Buffer Overflow

CVE-2026-41287 is a stack-based buffer overflow vulnerability in the Discovery Service component of WatchGuard Agent on Windows. The flaw affects WatchGuard Agent on Windows version 1.25.02.0000 and earlier. An unauthenticated attacker located on the same local network can send specially crafted requests to the discovery service, causing a stack memory buffer to overflow. Reported exploitation results in the agent service crashing, producing a denial-of-service condition.

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ANALYST BRIEF

Impact, mitigation & remediation

What it means. What to do now. Patch path, mitigations, and the assume-compromise checklist.

Impact

What an attacker gets, and what they’ve been doing with it.

Successful exploitation causes the WatchGuard Agent discovery service to crash, resulting in denial of service. This can temporarily disrupt endpoint security management and monitoring functions provided by the agent on the affected Windows system.

Mitigation

If you can’t patch tonight, do this now.

No specific workaround or mitigation short of patching is currently available. Exposure can be reduced by limiting access to the affected discovery service to trusted local network segments until the vendor update is applied.

Remediation

Patch, then assume compromise.

Upgrade WatchGuard Agent on Windows to version 1.25.03.0000 or later, as WatchGuard indicated that affected versions up to and including 1.25.02.0000 are vulnerable and that the vendor update addresses this issue.

PUBLIC EXPLOITS

Exploits

No public exploits tracked yet. Mallory keeps watching.

VALID 0 / 0 TOTALView more in app

No public exploit code observed for this vulnerability.

EXPOSURE SURFACE

Affected products & vendors

Products and vendors Mallory has correlated with this vulnerability. Open in Mallory to drill down to specific CPE configurations and version ranges.

VendorProductType

WatchGuard TechnologiesAgentapplication

WatchGuard TechnologiesSingle Watchguard Agentapplication

WatchGuard TechnologiesWatchguard Agentapplication

Vendor-confirmed product mapping. Mallory continuously reconciles this list against your asset inventory.

ACTIVITY FEED

Recent activity

5 sources tracked across advisories, community write-ups, and news. New activity surfaces here as Mallory finds it.

5 SOURCESView more in app

cyber security newsNews

May 7, 2026

WatchGuard Agent Vulnerabilities Let Attackers Grant Full SYSTEM Privileges on Windows

A stack-based buffer overflow vulnerability in the WatchGuard Agent for Windows discovery service that allows unauthenticated attackers on the same local network to trigger denial of service via crafted requests.

ca ccsNews

May 6, 2026

WatchGuard security advisory (AV26-428) - Canadian Centre for Cyber Security

A stack-based buffer overflow in the WatchGuard Agent Discovery Service on Windows that causes denial of service.

What this page doesn’t show

The version that knows your environment.

This page is what’s public. Mallory adds the parts that aren’t: which of your assets are affected, which adversaries are exploiting it right now, which detections to deploy, and what to do tonight.

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Exposure mapping

Query your assets running an affected version, and investigate the blast radius.

Threat actor evidence

Every observed campaign linking this CVE to a named adversary.

Associated malware

Malware families riding this exploit, with evidence and IOCs.

Detection signatures

YARA, Sigma, Snort, and vendor rules, auto-deployed to your SIEM.

Vendor-by-vendor mapping

Cross-references every affected SKU, including bundled OEM variants.

Social activity2