VYPR
High severity8.8NVD Advisory· Published Aug 6, 2020· Updated Jun 17, 2026

CVE-2020-13364

CVE-2020-13364

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.

Affected products

8
  • cpe:2.3:o:zyxel:nas326_firmware:*:*:*:*:*:*:*:*
    Range: <v5.21\(aazf.9\)c0
  • cpe:2.3:o:zyxel:nas520_firmware:*:*:*:*:*:*:*:*
    Range: <v5.21\(aasz.5\)c0
  • cpe:2.3:o:zyxel:nas540_firmware:*:*:*:*:*:*:*:*
    Range: <v5.21\(aatb.6\)c0
  • cpe:2.3:o:zyxel:nas542_firmware:*:*:*:*:*:*:*:*
    Range: <v5.21\(abag.6\)c0
  • Zyxel/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)C0description
  • Zyxel/NAS520llm-fuzzy
    Range: V5.21(AASZ.4)C0, V5.21(AASZ.0)C0, V5.11(AASZ.3)C0, V5.11(AASZ.0)C0
  • Zyxel/NSA325 V2llm-fuzzy
    Range: V4.81(AALS.0)C0 and V4.81(AAAJ.1)C0
  • Zyxel/NAS542llm-fuzzy
    Range: V5.11(ABAG.0)C0, V5.20(ABAG.1)C0, V5.21(ABAG.3)C0

Patches

Vulnerability mechanics

References

2

News mentions

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