CVE-2021-40521Network attack vector

Unauthenticated remote code execution

Published Nov 10, 2021 · Updated Aug 4, 2024

Remote code execution in Airangel HSMX Gateway devices through 5.2.04 allows remote attackers to execute code over the network. Published records do not disclose the vulnerable endpoint or the operation that processes attacker-controlled input. Exploitation requires network reachability but no authentication or user interaction, and successful execution permits arbitrary code in the gateway's context.

CVSS severity9.8
Critical
EPSS probability4.49%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Remote code execution in Airangel HSMX Gateway devices through 5.2.04 allows remote attackers to execute code over the network. Published records do not disclose the vulnerable endpoint or the operation that processes attacker-controlled input. Exploitation requires network reachability but no authentication or user interaction, and successful execution permits arbitrary code in the gateway's context.

The record

CVE
CVE-2021-40521
Published
Nov 10, 2021
Updated
Aug 4, 2024
Vendor
Unknown vendor
Product
Unknown product
Classifications
Unavailable
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Nov 10, 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

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Is a vulnerable build present?

Affected buildAffected product and version details are unavailable.

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Affected products and versions are unavailable in this record.

Published CVSS scores

9.8NIST NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
10.0NIST NVDAV:N/AC:L/Au:N/C:C/I:C/A:C

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)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

No sourced classifications are available.

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

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Your stack

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