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CVE-2020-9054

OS Command Injection: Is CVE-2020-9054 real, exploitable, or a false positive? Here's the community verdict.

signals

public sources

Exploited in wild
Yes
CISA KEV
Public exploit
PoC (unverified)
Metasploit/EDB/PoC
Base severity
9.8 Critical
CVSS
Exploitation prob.
100%
FIRST EPSS
Weakness
CWE-78 · OS Command Injection
CWE

Confirmed exploited in the wild. Patch this first, regardless of the base score.

public exploits

links to sources — we don’t host code

Unverified proof-of-concept code has been published. It may or may not be functional — assess before relying on it.

baseline read

auto · not a community verdict

Real — exploited in the wild

CISA confirms active exploitation. Treat scanner hits as true positives unless your specific version or config is unaffected.

Based on CISA KEV

Confirm or dispute →
Affected:Zyxel

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

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

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In your experience, is this finding real and exploitable?

awaiting field verdicts
Real, but not a risk here
Not a real issue

Curated baseline: TruePositive's read from public sources is Real & exploitable — a starting point, not a community verdict.

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Field notes & remediation

Verdicts are the quick signal. Notes are the evidence and fixes behind them.

  • 0
    Field note · TruePositive EditorialCurated

    Zyxel Multiple NAS Devices OS Command Injection Vulnerability — Multiple Zyxel network-attached storage (NAS) devices contain a pre-authentication command injection vulnerability, which may allow a remote, unauthenticated attacker to execute arbitrary code. Listed in the CISA KEV catalog (added 2022-03-25) — confirmed exploited in the wild, not theoretical. FIRST EPSS puts the chance of exploitation in the next 30 days at ~100%. Treat it as real and prioritize remediation over triage.

  • 0
    Remediation · TruePositive EditorialCurated

    Required action for Zyxel Multiple Network-Attached Storage (NAS) Devices: Apply updates per vendor instructions. CISA set a federal remediation due date of 2022-04-15. After patching, verify the vulnerable path is no longer reachable before closing the finding.

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Same weakness: CWE-78 · OS Command Injection.