CVE-2020-13365
highpriority · track · 35EPSS 0.010 · 62 %ileEUUSEPSS · scored 2026-10-27
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. This affects NAS520 V5.21(AASZ.4)C0, V5.21(AASZ.0)C0, V5.11(AASZ.3)C0, and V5.11(AASZ.0)C0; NAS542 V5.11(ABAG.0)C0, V5.20(ABAG.1)C0, and V5.21(ABAG.3)C0; NSA325 v2_V4.81(AALS.0)C0 and V4.81(AAAJ.1)C0; NSA310 4.22(AFK.0)C0 and 4.22(AFK.1)C0; NAS326 V5.21(AAZF.8)C0, V5.11(AAZF.4)C0, V5.11(AAZF.2)C0, and V5.11(AAZF.3)C0; NSA310S V4.75(AALH.2)C0; NSA320S V4.75(AANV.2)C0 and V4.75(AANV.1)C0; NSA221 V4.41(AFM.1)C0; and NAS540 V5.21(AATB.5)C0 and V5.21(AATB.3)C0.
cvss
Technical severity, 0–10. One row per scoring source.
base score 0–10 · higher = more severe · hover a vector to decode
weaknesses
The CWE weakness classes this flaw belongs to.
affected products (5)
Products and version ranges known to be affected.
also known as (3)
Other names and identifiers for this entity.
sources
Which sources assert this record, and when.
references (7)
External citations — patches, advisories, analysis.
- https://nvd.nist.gov/vuln/detail/CVE-2020-13365cnnvd
- https://www.zyxel.com/support/Zyxel-security-advisory-for-NAS-remote-access-vulnerability.shtmlcnnvd
- https://www.zyxel.com/us/en/support/security_advisories.shtmlcnnvd
- https://www.zyxel.com/support/Zyxel-security-advisory-for-NAS-remote-access-vulnerability.shtmlenisa_euvd
- https://www.zyxel.com/us/en/support/security_advisories.shtmlenisa_euvd
- https://www.zyxel.com/support/Zyxel-security-advisory-for-NAS-remote-access-vulnerability.shtmlVendor Advisorynvd
- https://www.zyxel.com/us/en/support/security_advisories.shtmlVendor Advisorynvd
Attackers weaponise vulnerabilities like this against internet-exposed services. See what is exposed on your perimeter with a free passive scan.
Free scan