CVE-2021-35032

Authenticated OS command execution via crafted function call

Published Dec 28, 2021 · Updated Aug 4, 2024

OS command injection in Zyxel GS1900 Series Firmware 2.60 allows local users to execute arbitrary OS commands via a crafted function call. The affected libsal.so library accepts crafted call data that reaches OS command execution, but Zyxel has not disclosed the function or sanitization failure. Exploitation requires authenticated local access to the switch and executes commands with the vulnerable function's privileges.

CVSS severity7.8
High
EPSS probability0.21%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
Coverage for this vulnerability

See if you're affected

Explore vulnerability checks for your environment with Hinoki.

Book a demo

Summary

What happened

OS command injection in Zyxel GS1900 Series Firmware 2.60 allows local users to execute arbitrary OS commands via a crafted function call. The affected libsal.so library accepts crafted call data that reaches OS command execution, but Zyxel has not disclosed the function or sanitization failure. Exploitation requires authenticated local access to the switch and executes commands with the vulnerable function's privileges.

The record

CVE
CVE-2021-35032
Published
Dec 28, 2021
Updated
Aug 4, 2024
Vendor
Zyxel Networks
Product
GS1900 Series Firmware
Classifications
CWE-78, T1059
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Dec 28, 2021CVE publishedPublication date reported by the CVE source.
  2. Aug 4, 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=2.60

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

Zyxel Networks · GS1900 Series Firmwareversion=2.60

Published CVSS scores

7.2NIST NVDAV:L/AC:L/Au:N/C:C/I:C/A:C
7.8NIST NVDCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
6.4Zyxel CorporationCVSS:3.1/AV:L/AC:H/PR:H/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 exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

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

Public exploit references

No public exploit references are available in this record.

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

Technologies

Your stack

See the directory against your own environment.

Your stack

Check the software in your environment

Book a demo to see how Hinoki identifies affected software and validates exploitability in your environment.

Book a demo