CVE-2020-13364: zyxel nas326_firmware
Vulnerability summary
CVE-2020-13364 is a high (CVSS 9.0) vulnerability in zyxel nas326_firmware. EPSS estimates a 1.15% chance of exploitation in the next 30 days, higher than 66.4% of scored vulnerabilities.
Timeline
- 06-08-2020PublishedVulnerability first disclosed.
- 04-08-2024Last modifiedVulnerability information updated.
Description
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.
CVSS metrics
4 scores · 2 sources · 3 versions- NVDNIST6.5MediumCVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N
EPSS trend
Probability
1.15%
Chance of exploitation in the next 30 days
Percentile
66%
Versus all other CVEs
30-day change
0.00 pp
From 1.15% on 20-09-2026
Known exploited
Compare KEV catalogsNot in any of the 3 tracked catalogs.
Public exploits
0 foundNo public exploits indexed.
Weaknesses
CWE · root causeNo weakness data has been published for this record.
Affected systems
Zyxel4 products
- nas326_firmware< v5.21\(aazf.9\)c0
- nas520_firmware< v5.21\(aasz.5\)c0
- nas540_firmware< v5.21\(aatb.6\)c0
- nas542_firmware< v5.21\(abag.6\)c0
1 vendor · 4 products
References
2 links- www.zyxel.com/support/Zyxel-security-advisory-for-NAS-remote-access-vulnerability.shtmlX Refsource MISCVendor Advisory