CVE-2020-13364

moderate-risk
Published 2020-08-06

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

Do I need to act?

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0.24% chance of exploitation
EPSS score — low exploit probability
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Not on CISA KEV list
No confirmed active exploitation reported to CISA
?
Patch status unknown
Check vendor advisories for fix availability and mitigation guidance
8
CVSS 8.8/10 High
NETWORK / LOW complexity

Affected Products (4)

Affected Vendors

Zyxel

References (4)

Vendor Advisory https://www.zyxel.com/support/Zyxel-security-advisory-for-NAS-remote-access-vuln...
Vendor Advisory https://www.zyxel.com/us/en/support/security_advisories.shtml
Vendor Advisory https://www.zyxel.com/support/Zyxel-security-advisory-for-NAS-remote-access-vuln...
Vendor Advisory https://www.zyxel.com/us/en/support/security_advisories.shtml
41
/ 100
moderate-risk
Severity 30/34 · Critical
Exploitability 1/34 · Minimal
Exposure 10/34 · Low