CVE-2022-26532Known exploitationPublic exploit

Root command execution via tcpdump argument injection

Published May 24, 2022 · Updated Aug 3, 2024

Argument injection in Zyxel appliance firmware allows local authenticated users to execute arbitrary OS commands through packet-trace. The zysh do_packet-trace function appends extension-filter input to a privileged tcpdump command line, permitting tcpdump options to invoke another program. Access to the CLI or authenticated Web Console as an admin or limited-admin user is required, and successful exploitation executes commands as root on the embedded device.

CVSS severity7.8
High
EPSS probability4.83%
Next 30 days · Sep 16, 2026
Known exploitationReported
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Argument injection in Zyxel appliance firmware allows local authenticated users to execute arbitrary OS commands through packet-trace. The zysh do_packet-trace function appends extension-filter input to a privileged tcpdump command line, permitting tcpdump options to invoke another program. Access to the CLI or authenticated Web Console as an admin or limited-admin user is required, and successful exploitation executes commands as root on the embedded device.

The record

CVE
CVE-2022-26532
Published
May 24, 2022
Updated
Aug 3, 2024
Vendor
Zyxel Networks
Product
Zyxel NAP203 Firmware
Classifications
CWE-88, CWE-78, T1059
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. May 24, 2022CVE publishedPublication date reported by the CVE source.
  2. Aug 3, 2024Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

Compare your product and version with the public record. A matching version still requires validation against your environment.

Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=<= 6.25(ABFA.7)

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

Zyxel Networks · Zyxel NAP203 Firmwareversion=<= 6.25(ABFA.7)
Zyxel Networks · USG FLEX Series Firmwareversion=4.50 through 5.21
Zyxel Networks · Zyxel NSG Series Firmwareversion=1.00 through 1.33 Patch 4
Zyxel Networks · WAC500 Firmwareversion=<= 6.30(ABVS.2)
Zyxel Networks · Zyxel NXC2500 Firmwareversion=<= 6.10(AAIG.3)
Zyxel Networks · WAX510D Firmwareversion=<= 6.30(ABTF.2)
Zyxel Networks · Zyxel ATP Series Firmwareversion=4.32 through 5.21
Zyxel Networks · NWA50AX Firmwareversion=<= 6.25(ABYW.5)
Zyxel Networks · Zyxel USG/ZyWALL Series Firmwareversion=4.09 through 4.71
Zyxel Networks · Zyxel VPN Series Firmwareversion=4.30 through 5.21

Published CVSS scores

7.2NISTAV:L/AC:L/Au:N/C:C/I:C/A:C
7.8Zyxel CorporationCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
Privilegesauthenticated
Known exploitationReported
Public exploitPublished

Weakness, pattern, technique

CWE-88Improper Neutralization of Argument Delimiters in a Command ('Argument Injection')
CWE-78Improper Neutralization of Special Elements used in an OS Command ('OS Command Injection')
T1059Command and Scripting Interpreter

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Reported exploitation

Technologies

Your stack

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Your stack

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