Is CVE-2024-11667 (Zyxel Multiple Firewalls Path Traversal) being exploited in the wild?

What the exploitation signal means for Zyxel firewall owners

The practical question is not whether the issue exists, but whether your environment has exposure to the vulnerable web management path. Internet-facing firewalls, appliances with management interfaces reachable from user networks, and devices that have not been inventoried recently should be treated as candidates for immediate verification. For edge appliances, the management plane is often the highest-value path into the environment, so even a narrow traversal flaw can have outsized impact.

Because the vulnerability sits in the web management interface, the first operational step is to confirm whether any Zyxel firewalls are deployed, whether the management interface is exposed, and whether those devices sit on critical network boundaries. That check matters even when the device is not directly public, since an internal foothold can still use a reachable management plane to reach sensitive configuration and file paths.

Affected teams should also assume that exploitation is not hypothetical once a vulnerability reaches the CISA KEV catalogue. For edge-device triage and emergency response, NHIMG’s Edge Device Security Guide is the most relevant internal starting point because it focuses on management exposure, appliance credentials, logging minimums and patch discipline for internet-facing appliances.

Why path traversal on a firewall becomes a high-impact issue

Path traversal in a management interface is dangerous because it can let an attacker reach files outside the intended application boundary. On a firewall, those files may include configuration material, logs, uploaded content, or other data handled by the management service. If the interface also allows file upload, the same weakness can expand from read access into write access, which can materially change the attacker’s options.

That is why this class of flaw is usually treated as more than a simple web bug. In the wrong place, it can become a control-plane compromise, not just an application error. Attackers target edge devices precisely because they sit at trust boundaries and often have elevated visibility, broad network reach, and privileged administrative functions.

For a broader playbook on exploitation patterns and response sequencing, NHIMG’s Zero-Day and Exploited Vulnerabilities Guide helps frame what to do when a flaw has moved from disclosure to active exploitation, while Web Application Attacks Guide covers the underlying traversal mechanics that make this kind of issue so persistent.

How to verify exposure and respond before patching is complete

Start by identifying all Zyxel firewall instances, then verify whether the web management interface is enabled, reachable, and restricted to trusted administrative paths. If you cannot patch immediately, the next best control is to reduce exposure aggressively: restrict access to the management plane, segment it away from general user traffic, and increase logging and alerting around administrative access and file activity.

Where there is any sign of suspicious access, treat the device as potentially touched and look for evidence of file reads, file writes, odd management sessions, configuration changes, or unexpected uploads. On appliances, compromise assessment matters because attackers often use the initial foothold to harvest secrets, alter configuration, or stage follow-on access even when the original bug is narrow.

For response prioritisation, NHIMG’s Vulnerability Management Guide is useful for triage, exception handling and remediation tracking, and Ivanti Connect Secure exploitation 2024 shows why exposed edge appliances often require both patching and compromise assessment, not just a software update.

Risk and Threat Considerations

Exploitability is especially concerning when the affected firewall is a boundary device with administrative reach. A path traversal flaw in that role can expose configuration data, support unauthorized file access, and create a route to deeper compromise if the attacker can tamper with management content or use the device as a stepping stone.

Failure mechanism: The attacker abuses unsanitized URL path handling in the web management interface to move outside the intended directory scope and access or place files that the management service should not expose.

Impact: A successful exploit can lead to information disclosure, unauthorized modification, broader appliance compromise, and in some environments a pathway into internal trust zones or downstream credential exposure.

Practitioner Guidance

What to verify: Confirm inventory coverage first, then validate whether each Zyxel firewall has a reachable management interface, whether it is internet-exposed, and whether logs are retained long enough to support a compromise review. If you cannot answer those three questions quickly, the device is not being governed tightly enough for an exploited edge appliance.

Decision rule: If the device is exposed or cannot be confidently assessed, treat it as high priority for emergency remediation and forensic review. If patch timing is delayed, remove unnecessary access paths to the management plane and assume the device may already have been probed.

Practitioner takeaway: For edge firewalls, “known exploited” should trigger both exposure reduction and compromise hunting, because the main risk is not just the bug itself but what an attacker can do once they reach the management plane.

Related resources from NHI Mgmt Group

• How do you patch or mitigate CVE-2024-11667 (Zyxel Multiple Firewalls Path Traversal)?
• CVE-2024-11667 (Zyxel Multiple Firewalls Path Traversal)
• Is CVE-2024-13159 (Ivanti Endpoint Manager (EPM) Absolute Path Traversal) being exploited in the wild?
• Is CVE-2024-13161 (Ivanti Endpoint Manager (EPM) Absolute Path Traversal) being exploited in the wild?