CVE-2021-43663Public exploit

Root command execution via hijacked update response

Published Mar 30, 2022 · Updated Aug 4, 2024

OS command injection in TOTOLINK EX300_v2 V4.0.3c.140_B20210429 allows man-in-the-middle attackers to execute code as root. The cloudupdate_check handler inserts untrusted magicid and url values from an HTTP update response into echo commands without neutralization, then passes them to system(). Exploitation requires an adjacent attacker able to hijack DNS or the cleartext firmware-server request; successful commands run with root privileges on the repeater.

CVSS severity7.5
High
EPSS probability0.96%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

OS command injection in TOTOLINK EX300_v2 V4.0.3c.140_B20210429 allows man-in-the-middle attackers to execute code as root. The cloudupdate_check handler inserts untrusted magicid and url values from an HTTP update response into echo commands without neutralization, then passes them to system(). Exploitation requires an adjacent attacker able to hijack DNS or the cleartext firmware-server request; successful commands run with root privileges on the repeater.

The record

CVE
CVE-2021-43663
Published
Mar 30, 2022
Updated
Aug 4, 2024
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-77, T1557, T1059.004
Attack vector
adjacent
Privileges
unauthenticated

Timeline

How it unfolded

  1. Mar 30, 2022CVE 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

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Is a vulnerable build present?

Affected buildAffected product and version details are unavailable.

What conditions does exploitation require?

Attack vectoradjacent
Required privilegesunauthenticated

What is affected?

Affected products and versions are unavailable in this record.

Published CVSS scores

7.9NIST NVDAV:A/AC:M/Au:N/C:C/I:C/A:C
7.5NIST NVDCVSS:3.1/AV:A/AC:H/PR:N/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)
Vectoradjacent
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-77Improper Neutralization of Special Elements used in a Command ('Command Injection')
T1557Adversary-in-the-Middle
T1059.004Unix Shell

Public exploit references

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

Technologies

Your stack

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Your stack

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