CVE-2021-22787Network attack vector

Device service interruption via crafted HTTP request

Published Feb 11, 2022 · Updated May 29, 2026

Improper input validation in Schneider Electric Modicon web servers allows remote attackers to interrupt affected devices via crafted HTTP requests. Schneider Electric has not disclosed which HTTP field or parser operation mishandles the crafted input; the public record identifies only the embedded web server. No authentication or user interaction is required, and the documented consequence is an availability-only service interruption.

CVSS severity7.5
High
EPSS probability1.04%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Improper input validation in Schneider Electric Modicon web servers allows remote attackers to interrupt affected devices via crafted HTTP requests. Schneider Electric has not disclosed which HTTP field or parser operation mishandles the crafted input; the public record identifies only the embedded web server. No authentication or user interaction is required, and the documented consequence is an availability-only service interruption.

The record

CVE
CVE-2021-22787
Published
Feb 11, 2022
Updated
May 29, 2026
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-20, T0814
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Feb 11, 2022CVE publishedPublication date reported by the CVE source.
  2. May 29, 2026Record 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

7.5CISA-ADPCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
7.5NIST NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
5.0NIST NVDAV:N/AC:L/Au:N/C:N/I:N/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-20Improper Input Validation
T0814Denial of Service

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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