CVE-2021-22790Network attack vector

Service interruption via out-of-bounds project parsing

Published Sep 2, 2021 · Updated May 29, 2026

Out-of-bounds read in Schneider Electric Modicon controllers and PLC simulators allows remote authenticated users to interrupt service. Schneider Electric has not identified the affected parser or disclosed how crafted project data triggers the out-of-bounds read. The attacker must have network access and privileges to download the project; successful processing causes loss of availability, though the vendor does not identify whether the target hangs, crashes, or reboots.

CVSS severity6.5
Medium
EPSS probability0.84%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Out-of-bounds read in Schneider Electric Modicon controllers and PLC simulators allows remote authenticated users to interrupt service. Schneider Electric has not identified the affected parser or disclosed how crafted project data triggers the out-of-bounds read. The attacker must have network access and privileges to download the project; successful processing causes loss of availability, though the vendor does not identify whether the target hangs, crashes, or reboots.

The record

CVE
CVE-2021-22790
Published
Sep 2, 2021
Updated
May 29, 2026
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-125, T0826
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Sep 2, 2021CVE 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 privilegesauthenticated

What is affected?

Affected products and versions are unavailable in this record.

Published CVSS scores

6.5NIST NVDCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
6.5Schneider Electric SECVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
6.5CISA-ADPCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
4.0NIST NVDAV:N/AC:L/Au:S/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 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-125Out-of-bounds Read
T0826Loss of Availability

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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