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CVE-2023-27988

HIGH
7.2
CVSS Score
Published: May 30, 2023 at 12:00 AM UTC
Updated: June 17, 2026 at 05:46 AM UTC
6 products affected across 1 vendorNAS326 firmwareNAS542 firmwareNAS540 firmware

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Severity
HIGH7.2
Exploit prediction
EPSS 1%
SSVC
No known exploit

Description

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.

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

NAS326 firmware· Zyxel
95%
v < 5.21(aazf.13)c0< V5.21(AAZF.13)C0
Affected range stops below 5.21(aazf.13)c0, so it looks safe — our inference, not a vendor statement
zyxel-nas326 (same device)
NAS540 firmware· Zyxel
95%
v < 5.21(aatb.10)c0
Affected range stops below 5.21(aatb.10)c0, so it looks safe — our inference, not a vendor statement
zyxel-nas540 (same device)
NAS542 firmware· Zyxel
95%
v < 5.21(abag.10)c0
Affected range stops below 5.21(abag.10)c0, so it looks safe — our inference, not a vendor statement
zyxel-nas542 (same device)
Nas326· Zyxeldevice
80%
All versions
Nas540· Zyxeldevice
80%
All versions
Nas542· Zyxeldevice
80%
All versions

Remediation

No guide yet

No remediation guidance has been written for this CVE yet. What the record does show:

Patch and advisory references

References (1)

PatchVendor Advisory
Source: [email protected]
https://www.zyxel.com/global/en/support/security-advisories/zyxel-security-advisory-for-post-authentication-command-injection-vulnerability-in-nas-products

SSVC — Action Prioritization

SSVCNo known exploitNot automatableTotal impact

SSVC signals action urgency (what to patch first), separate from CVSS which measures severity.

CVSS

7.2HIGHZyxel
Attack Vector
NETWORK
Complexity
LOW
Privileges
HIGH
User Interaction
NONE
Scope
UNCHANGED
Confidentiality
HIGH
Integrity
HIGH
Availability
HIGH
Vector?

Quick Info

StatusMODIFIED
CWE
CWE-78

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