Exploitation evidence
Known exploited · CISA KEV listed
Added 2022-03-25. Ransomware campaign use: Unknown.
CISA required action: Apply updates per vendor instructions.
CISA due date: 2022-04-15. This is the catalog’s deadline, not an assessment of your organization’s exposure.
KEV checked 13 Nov 2026, 00:20 Jerusalem · Original catalog ↗Reported products and versions
ZyXEL / NAS326
Default status: Not specified
- affected: V5.21(AAZF.7)C0 to ≤ V5.21(AAZF.7)C0 (custom)
ZyXEL / NAS520
Default status: Not specified
- affected: V5.21(AASZ.3)C0 to ≤ V5.21(AASZ.3)C0 (custom)
ZyXEL / NAS540
Default status: Not specified
- affected: V5.21(AATB.4)C0 to ≤ V5.21(AATB.4)C0 (custom)
ZyXEL / NAS542
Default status: Not specified
- affected: V5.21(ABAG.4)C0 to ≤ V5.21(ABAG.4)C0 (custom)
ZyXEL / NSA210
Default status: Not specified
- affected: all
ZyXEL / NSA220
Default status: Not specified
- affected: all
ZyXEL / NSA220+
Default status: Not specified
- affected: all
ZyXEL / NSA221
Default status: Not specified
- affected: all
ZyXEL / NSA310
Default status: Not specified
- affected: V4.75(AALH.2)C0 to ≤ V4.75(AALH.2)C0 (custom)
ZyXEL / NSA320
Default status: Not specified
- affected: all
ZyXEL / NSA320S
Default status: Not specified
- affected: V4.75(AANV.2)C0 to ≤ V4.75(AANV.2)C0 (custom)
ZyXEL / NSA325
Default status: Not specified
- affected: V4.81(AAAJ.1)C0 to ≤ V4.81(AAAJ.1)C0 (custom)
ZyXEL / NSA325v2
Default status: Not specified
- affected: V4.81(AALS.1)C0 to ≤ V4.81(AALS.1)C0 (custom)
Fixes and workarounds
ZyXEL has made firmware updates available for NAS326, NAS520, NAS540, NAS542, ATP100, ATP200, ATP500, ATP800, USG20-VPN, USG20W-VPN, USG40, USG40W, USG60, USG60W, USG110, USG210, USG310, USG1100, USG1900, USG2200, VPN50, VPN100, VPN300, VPN1000, ZyWALL110, ZyWALL310, and ZyWALL1100 devices.
Reported workarounds: Block access to the ZyXEL device web interface: This issue can be mitigated by blocking (for example with a firewall) access to the web interface (80/tcp and 443/tcp) of any vulnerable ZyXEL device. Any machine that can access the ZyXEL web interface should not also be able to access the internet. Restrict access to vulnerable ZyXEL devices: Direct exploitation of this vulnerability can be mitigated by restricting access to vulnerable devices. In particular, do not expose such devices directly to the internet. Note however, that it is still possible for attackers to exploit devices that are not directly connected to the internet. For example, by way of viewing a web page.
Sources and related reporting
CVE Program record ↗ · Download tracked evidence as JSON
- https://cwe.mitre.org/data/definitions/78.html
- https://www.zyxel.com/support/remote-code-execution-vulnerability-of-NAS-products.shtml
- https://kb.cert.org/vuls/id/498544/
- https://kb.cert.org/artifacts/cve-2020-9054.html
- https://krebsonsecurity.com/2020/02/zyxel-fixes-0day-in-network-storage-devices/
- https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2020-9054
Observed change timeline
History begins when Egret first downloads each source. It is not the complete upstream CVE history.
12 Nov 2026, 18:20 Jerusalem · EPSS observation updated
Stored EPSS snapshot at this observation.
{
"date": "2026-11-12",
"epss": 0.99988,
"percentile": 0.99984
}10 Nov 2026, 18:20 Jerusalem · EPSS observation updated
Stored EPSS snapshot at this observation.
{
"date": "2026-11-10",
"epss": 0.99988,
"percentile": 0.99984
}09 Nov 2026, 18:20 Jerusalem · EPSS observation updated
Stored EPSS snapshot at this observation.
{
"date": "2026-11-09",
"epss": 0.99988,
"percentile": 0.99984
}08 Nov 2026, 18:20 Jerusalem · EPSS observation updated
Stored EPSS snapshot at this observation.
{
"date": "2026-11-08",
"epss": 0.99988,
"percentile": 0.99984
}07 Nov 2026, 18:20 Jerusalem · EPSS observation updated
Stored EPSS snapshot at this observation.
{
"date": "2026-11-07",
"epss": 0.99988,
"percentile": 0.99984
}06 Nov 2026, 18:20 Jerusalem · EPSS observation updated
Stored EPSS snapshot at this observation.
{
"date": "2026-11-06",
"epss": 0.99988,
"percentile": 0.99984
}06 Nov 2026, 00:20 Jerusalem · CVE Program record changed
Stored CNA snapshot at this observation.
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}05 Nov 2026, 18:20 Jerusalem · EPSS observation updated
Stored EPSS snapshot at this observation.
{
"date": "2026-11-05",
"epss": 0.99988,
"percentile": 0.99984
}04 Nov 2026, 18:20 Jerusalem · EPSS observation updated
Stored EPSS snapshot at this observation.
{
"date": "2026-11-04",
"epss": 0.99988,
"percentile": 0.99984
}03 Nov 2026, 18:20 Jerusalem · EPSS observation updated
Stored EPSS snapshot at this observation.
{
"date": "2026-11-03",
"epss": 0.99988,
"percentile": 0.99984
}03 Nov 2026, 02:22 Jerusalem · EPSS observation updated
Stored EPSS snapshot at this observation.
{
"date": "2026-11-02",
"epss": 0.99988,
"percentile": 0.99984
}03 Nov 2026, 02:22 Jerusalem · CISA KEV status changed
Stored KEV snapshot at this observation.
{
"cveID": "CVE-2020-9054",
"cwes": [
"CWE-78"
],
"dateAdded": "2022-03-25",
"dueDate": "2022-04-15",
"forensicTriage": "No",
"knownRansomwareCampaignUse": "Unknown",
"notes": "https://nvd.nist.gov/vuln/detail/CVE-2020-9054",
"product": "Multiple Network-Attached Storage (NAS) Devices",
"requiredAction": "Apply updates per vendor instructions.",
"shortDescription": "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.",
"vendorProject": "Zyxel",
"vulnerabilityName": "Zyxel Multiple NAS Devices OS Command Injection Vulnerability"
}