CVE-2020-13364
High
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.
SeverityHigh
CVSS8.8
Exploit probability—
Product
Zyxel Nas326 Firmware
PublishedAug 6, 2020
First seenAug 6, 2020
How to fix
Update
- zyxel nas326_firmwarev5.21\(aazf.9\)c0 or later
- zyxel nas520_firmwarev5.21\(aasz.5\)c0 or later
- zyxel nas540_firmwarev5.21\(aatb.6\)c0 or later
- zyxel nas542_firmwarev5.21\(abag.6\)c0 or later
Affected products
| Product | Affected versions | Fixed in |
|---|---|---|
| zyxel nas326_firmware | v < v5.21\(aazf.9\)c0 | v5.21\(aazf.9\)c0 |
| zyxel nas520_firmware | v < v5.21\(aasz.5\)c0 | v5.21\(aasz.5\)c0 |
| zyxel nas540_firmware | v < v5.21\(aatb.6\)c0 | v5.21\(aatb.6\)c0 |
| zyxel nas542_firmware | v < v5.21\(abag.6\)c0 | v5.21\(abag.6\)c0 |
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