Nas520 Firmware vulnerabilitiesAnd the versions its exploited flaws hit.

Product1 known exploited2 versions
The short answer

Nas520 Firmware is made by Zyxel. We track 3 published vulnerabilities in it, across 2 versions. 1 of them is on the list of flaws known to be exploited, the newest added on 25 March 2022. If you run Nas520 Firmware, check your version against the exploited flaws below and patch those first.

Check your version

The most recent Nas520 Firmware flaw added to the known-exploited list is CVE-2020-9054, on 25 March 2022. We keep watching the known-exploited list.

Versions

Which versions of Nas520 Firmware do the exploited flaws hit?

Each exploited flaw lists the versions it affects, usually as ranges. "before 5.21(aasz.3)c0" means every version up to, but not including, 5.21(aasz.3)c0. Find your version, then patch.

  • CVE-2020-9054Exploited list, 25 Mar 2022

    Zyxel Multiple NAS Devices OS Command Injection Vulnerability

    before 5.21(aasz.3)c0
Known exploited

Which Nas520 Firmware vulnerabilities are being exploited?

1 flaw is on the government list of vulnerabilities known to be exploited. These are the ones criminals are using now, so they go first, whatever their severity score says.

  1. 9.8
    CVE-2020-9054CriticalKnown exploited
    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.

    Chance of use>99%Known exploited since25 Mar 2022
Exploit likelihood

Which Nas520 Firmware flaws are most likely to be used?

Ranked by the latest exploit-likelihood forecast: the chance each flaw is used in an attack in the next 30 days. A high severity score on its own doesn't tell you that. Flaws shared by many other makers' products are left out.

50% or more10% to 49%Under 10%
  1. >99%
    CVE-2020-9054CriticalKnown exploited

    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...

    CVSS9.8Published4 Mar 2020
  2. 1.2%

    A backdoor in certain Zyxel products allows remote TELNET access via a CGI script.

    CVSS8.8Published6 Aug 2020
  3. 1.0%

    Certain Zyxel products have a locally accessible binary that allows a non-root user to generate a password for an undocumented user account that can be used for a TELNET session as root.

    CVSS8.8Published6 Aug 2020
Precursor Intelligence

Running Nas520 Firmware? We'll keep checking.

Looking flaws up one at a time doesn't scale. Tell us what you run once, and we tell you which flaws matter to you, in what order, and keep watching for new ones.

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We track 3 published vulnerabilities listed under the name Nas520 Firmware, across 2 versions. The most recent Nas520 Firmware flaw added to the known-exploited list is CVE-2020-9054, on 25 March 2022.

1 is on the list of flaws known to be exploited. The most recently added is CVE-2020-9054.

Each flaw names its own versions, usually as ranges. The newest, CVE-2020-9054, affects before 5.21(aasz.3)c0. The versions for every exploited flaw are listed on this page.

Create a Precursor Intelligence account and track Nas520 Firmware. We match it against every published flaw, give each one a risk score from 0 to 100 and keep watching, so you hear about new ones as soon as we know, by email, in the app or by webhook.