CVE-2021-22731Network attack vector

Unauthorized password changes via weak recovery verification

Published May 26, 2021 · Updated Aug 3, 2024

Weak password recovery in Schneider Electric Modicon Managed Switch 8.21 and earlier allows remote attackers to change passwords over HTTP or HTTPS. The web password-recovery workflow accepts basic user information as sufficient identity proof and permits a replacement password without the existing password. Network access to the management service and knowledge of basic user information are sufficient to take over an account by replacing its password.

CVSS severity9.8
Critical
EPSS probability1.40%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Weak password recovery in Schneider Electric Modicon Managed Switch 8.21 and earlier allows remote attackers to change passwords over HTTP or HTTPS. The web password-recovery workflow accepts basic user information as sufficient identity proof and permits a replacement password without the existing password. Network access to the management service and knowledge of basic user information are sufficient to take over an account by replacing its password.

The record

CVE
CVE-2021-22731
Published
May 26, 2021
Updated
Aug 3, 2024
Vendor
Schneider Electric
Product
Modicon Managed Switch
Classifications
CWE-640, T1098
Attack vector
network
Privileges
unauthenticated

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?

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

  1. Affected versionversion=Modicon Managed Switch MCSESM* and MCSESP* V8.21 and prior

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Schneider Electric · Modicon Managed Switchversion=Modicon Managed Switch MCSESM* and MCSESP* V8.21 and prior

Published CVSS scores

9.8NIST NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
7.5NIST NVDAV:N/AC:L/Au:N/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
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-640Weak Password Recovery Mechanism for Forgotten Password
T1098Account Manipulation

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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