OMENWAVE modelled vulnerability-chaining pathways

CVE-2020-9054

Multiple ZyXEL network-attached storage (NAS) devices running firmware version 5.21 contain a pre-authentication command injection vulnerability, which may allow a remote, unauthenticated attacker to execute arbitrary code on a vulnerable device. ZyXEL NAS devices achieve authentication by using the weblogin.cgi CGI executable. This program fails to properly sanitize the username parameter that is passed to it. If the username parameter contains certain characters, it can allow command injection with the privileges of the web server that runs on the ZyXEL device. Although the web server does not run as the root user, ZyXEL devices include a setuid utility that can be leveraged to run any command with root privileges. As such, it should be assumed that exploitation of this vulnerability can lead to remote code execution with root privileges. By sending a specially-crafted HTTP POST or GET request to a vulnerable ZyXEL device, a remote, unauthenticated attacker may be able to execute arbitrary code on the device. This may happen by directly connecting to a device if it is directly exposed to an attacker. However, there are ways to trigger such crafted requests even if an attacker does not have direct connectivity to a vulnerable devices. For example, simply visiting a website can result in the compromise of any ZyXEL device that is reachable from the client system. Affected products include: NAS326 before firmware V5.21(AAZF.7)C0 NAS520 before firmware V5.21(AASZ.3)C0 NAS540 before firmware V5.21(AATB.4)C0 NAS542 before firmware V5.21(ABAG.4)C0 ZyXEL has made firmware updates available for NAS326, NAS520, NAS540, and NAS542 devices. Affected models that are end-of-support: NSA210, NSA220, NSA220+, NSA221, NSA310, NSA310S, NSA320, NSA320S, NSA325 and NSA325v2

9.8
CVSS Critical
100.0%
EPSS p100
YES
In CISA KEV

Data as of 2 Nov 2026 · NVD, CISA KEV, EPSS

Why chaining, at machine speed

Defenders still triage vulnerabilities one CVE at a time, while increasingly automated attackers combine them at machine speed. Omenwave models the plausible pathways by which this CVE could be chained with others — surfacing them for research and awareness, with evidence for each step.

Modelled capability profile
Kill-chain stage
INITIAL_ACCESS
Requires
NONE access, NETWORK vector
Grants
USER access
Capabilities
code execution
Model confidence
high · CVSS 3.1
Top plausible next hops
CVE-2025-49704INITIAL_ACCESS → EXECUTIONhigh plausibility · KEV

The access level the source grants already meets or exceeds the access level the destination requires — the position carries over.

Improper control of generation of code ('code injection') in Microsoft Office SharePoint allows an authorized attacker to execute code over a network.

CVE-2022-41040INITIAL_ACCESS → EXECUTIONhigh plausibility · KEV

The access level the source grants already meets or exceeds the access level the destination requires — the position carries over.

Microsoft Exchange Server Elevation of Privilege Vulnerability

CVE-2020-0688INITIAL_ACCESS → EXECUTIONhigh plausibility · KEV

The access level the source grants already meets or exceeds the access level the destination requires — the position carries over.

A remote code execution vulnerability exists in Microsoft Exchange software when the software fails to properly handle objects in memory, aka 'Micros…

CVE-2025-49113INITIAL_ACCESS → EXECUTIONhigh plausibility · KEV

The access level the source grants already meets or exceeds the access level the destination requires — the position carries over.

Roundcube Webmail before 1.5.10 and 1.6.x before 1.6.11 allows remote code execution by authenticated users because the _from parameter in a URL is n…

CVE-2020-11978INITIAL_ACCESS → EXECUTIONhigh plausibility · KEV

The access level the source grants already meets or exceeds the access level the destination requires — the position carries over.

An issue was found in Apache Airflow versions 1.10.10 and below. A remote code/command injection vulnerability was discovered in one of the example D…

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Modelled plausible chaining potential derived from public CVE metadata (CVSS, CWE, CPE). Not a confirmed real-world exploit chain and contains no exploitation detail. For research and awareness only.

Methodology · Interactive explorer · JSON: /cve/CVE-2020-9054