OS command injection in Zyxel NAS326 firmware
Priority LOW 36CWE-78Published · Updated
Key facts
- Attack vector
- Network
- Privileges required
- High
- User interaction
- None
- Attack complexity
- Low
- Impact type
- Code execution
- Confidentiality · integrity · availability
- High · High · High
- Fix status
- Fixed
Attack profile from CVSS 3.1 · CNA. Fix status from CNA. Impact type from CWE-78.
Summary
The post-authentication command injection vulnerability in the Zyxel NAS326 firmware versions prior to V5.21(AAZF.13)C0 could allow an authenticated attacker with administrator privileges to execute some operating system (OS) commands on an affected device remotely.
Why it matters now
Exploitation None reported CISA SSVC · not in CISA KEV
EPSS 0.01363 71st percentileScored 2026-11-07
Fix Fixed NAS326 firmware (Zyxel): V5.21(AAZF.13)C0
SSVC decision points
CISA ADP · SSVC 2.0.3
- Exploitation
- None
- Automatable
- No
- Technical impact
- Total
The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.
Affected products
| Vendor | Product | Affected versions | Fixed in | Status | Source |
|---|---|---|---|---|---|
| Zyxel | NAS326 firmware | before V5.21(AAZF.13)C0 | V5.21(AAZF.13)C0 | Patch available | CNA |
- NAS326 firmware VendorZyxel Affected before V5.21(AAZF.13)C0 Fixed in V5.21(AAZF.13)C0 Patch available CNA
CPE configurations NVD · 6
| CPE | Versions | Role | Vendor |
|---|---|---|---|
| cpe:2.3:o:zyxel:nas326_firmware:*:*:*:*:*:*:*:* | before 5.21\(aazf.13\)c0 | Vulnerable | Zyxel |
| cpe:2.3:h:zyxel:nas326:-:*:*:*:*:*:*:* | not specified by NVD | Running on | Zyxel |
| cpe:2.3:o:zyxel:nas540_firmware:*:*:*:*:*:*:*:* | before 5.21\(aatb.10\)c0 | Vulnerable | Zyxel |
| cpe:2.3:h:zyxel:nas540:-:*:*:*:*:*:*:* | not specified by NVD | Running on | Zyxel |
| cpe:2.3:o:zyxel:nas542_firmware:*:*:*:*:*:*:*:* | before 5.21\(abag.10\)c0 | Vulnerable | Zyxel |
| cpe:2.3:h:zyxel:nas542:-:*:*:*:*:*:*:* | not specified by NVD | Running on | Zyxel |
- cpe:2.3:o:zyxel:nas326_firmware:*:*:*:*:*:*:*:* Versions before 5.21\(aazf.13\)c0 Vulnerable ·Zyxel
- cpe:2.3:h:zyxel:nas326:-:*:*:*:*:*:*:* Versions not specified by NVD Running on ·Zyxel
- cpe:2.3:o:zyxel:nas540_firmware:*:*:*:*:*:*:*:* Versions before 5.21\(aatb.10\)c0 Vulnerable ·Zyxel
- cpe:2.3:h:zyxel:nas540:-:*:*:*:*:*:*:* Versions not specified by NVD Running on ·Zyxel
- cpe:2.3:o:zyxel:nas542_firmware:*:*:*:*:*:*:*:* Versions before 5.21\(abag.10\)c0 Vulnerable ·Zyxel
- cpe:2.3:h:zyxel:nas542:-:*:*:*:*:*:*:* Versions not specified by NVD Running on ·Zyxel
Remediation
- Fix · CNA NAS326 firmware (Zyxel) Fixed in V5.21(AAZF.13)C0
Timeline
- 2026-10-02 Threatist record created from CVE-2023-27988
- 2026-10-03 Alias added: GHSA-wc8j-6g5m-3r95
More Zyxel Nas326 Firmware vulnerabilities
- TI-2023-12582 OS command injection in Zyxel NAS326 firmware KEVCVSS 3.1CRITICAL 9.8
- TI-2020-07267 OS command injection in Zyxel NAS326 KEVCVSS 3.1CRITICAL 9.8
- TI-2024-19735 OS command injection in Zyxel NAS326 firmware CVSS 3.1CRITICAL 9.8
- TI-2024-19736 OS command injection in Zyxel NAS326 firmware CVSS 3.1CRITICAL 9.8
- TI-2023-04130 OS command injection in Zyxel NAS326 firmware CVSS 3.1CRITICAL 9.8
- TI-2023-04129 OS command injection in Zyxel NAS326 firmware CVSS 3.1CRITICAL 9.8
Sources
- CVE-2023-27988 · CVE Program
- CVE-2023-27988 · NVD
- FIRST EPSS
- GHSA-wc8j-6g5m-3r95 · GitHub Advisory Database · CC BY 4.0
This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences