CVE-2021-22735Network attack vector

Authenticated code execution via unsigned firmware upload

Published May 26, 2021 · Updated Aug 3, 2024

Improper signature verification in Schneider Electric homeLYnk and spaceLYnk 2.60 and earlier allows remote authenticated users to execute code. The firmware installation path accepts copied code without properly validating its cryptographic signature before execution. Administrative access is required over the network, and successful exploitation runs attacker-supplied code on the automation controller.

CVSS severity7.2
High
EPSS probability1.00%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Improper signature verification in Schneider Electric homeLYnk and spaceLYnk 2.60 and earlier allows remote authenticated users to execute code. The firmware installation path accepts copied code without properly validating its cryptographic signature before execution. Administrative access is required over the network, and successful exploitation runs attacker-supplied code on the automation controller.

The record

CVE
CVE-2021-22735
Published
May 26, 2021
Updated
Aug 3, 2024
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-347
Attack vector
network
Privileges
admin

Timeline

How it unfolded

  1. May 26, 2021CVE 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

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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 privilegesadmin

What is affected?

Affected products and versions are unavailable in this record.

Published CVSS scores

7.2NIST NVDCVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H
6.5NIST NVDAV:N/AC:L/Au:S/C:P/I:P/A:P

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
Privilegesadmin
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-347Improper Verification of Cryptographic Signature

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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