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VulnerabilityPublished Updated

CVE-2023-27992: Zyxel NAS326 firmware · OS Command Injection

Affects Zyxel NAS326 firmwareSource CVE Database V5

0

Exploited in the wild · KEV due 14 Jul 2023 · 82% EPSS : apply the vendor's fix or mitigations to Zyxel NAS326 firmware now.

Data as of 26 Oct 2026, 17:16 UTC

CVSS 3.1 base score
9.8Critical
How severe the flaw is on the 0–10 CVSS scale.
KEV deadline
 US federal agencies must patch by this date; a sensible deadline for everyone else. Other KEV due dates
EPSS
82.2% chance of exploitation in 30 days – higher than 99% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Exploitation evidence

t = 0 is the CVE’s publication on cve.org

  1. Disclosed: evidence found.

    CVE published 19 Jun 2023

  2. Detectable: no evidence on record.

    No public nuclei template indexed

  3. Weaponised: no evidence on record.

    No public exploit code indexed in Metasploit or Exploit-DB

  4. Exploited in the wild: evidence found.

    Listed in CISA KEV 4 days after disclosure

  5. Observed by OffSeq Mirage: no evidence on record.

    No attack traffic recorded by OffSeq Mirage sensors

Timeline

  1. CVE ID reserved

    by Zyxel Corporation

    , 102 days before disclosure

  2. CVE published

    on cve.org

    , t = 0

  3. , 4 days after disclosure

  4. KEV remediation due

    US federal deadline

    , 25 days after disclosure

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), CISA KEV (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 26 Oct 2026.

What to do

Check the firmware or software version for Zyxel NAS326 firmware in the device's admin interface against the vendor advisory.

Description

The pre-authentication command injection vulnerability in the Zyxel NAS326 firmware versions prior to V5.21(AAZF.14)C0, NAS540 firmware versions prior to V5.21(AATB.11)C0, and NAS542 firmware versions prior to V5.21(ABAG.11)C0 could allow an unauthenticated attacker to execute some operating system (OS) commands remotely by sending a crafted HTTP request.

References

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