CVE-2021-37182Network attack vector

Network interruption via unchecked OSPF LS Updates

Published Jun 14, 2022 · Updated Aug 4, 2024

Denial of service in Siemens SCALANCE XM-400 and XR-500 devices before 6.5 allows remote attackers to interrupt network traffic. The OSPF implementation processes LS Update messages without verifying their checksum and length fields, allowing malformed packets to disrupt routing. No authentication or user interaction is required, but OSPF must be enabled; Siemens states that OSPF is disabled by default.

CVSS severity5.9
Medium
EPSS probability0.62%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Denial of service in Siemens SCALANCE XM-400 and XR-500 devices before 6.5 allows remote attackers to interrupt network traffic. The OSPF implementation processes LS Update messages without verifying their checksum and length fields, allowing malformed packets to disrupt routing. No authentication or user interaction is required, but OSPF must be enabled; Siemens states that OSPF is disabled by default.

The record

CVE
CVE-2021-37182
Published
Jun 14, 2022
Updated
Aug 4, 2024
Vendor
Siemens
Product
SCALANCE XR526-8C, 2x230V
Classifications
CWE-354, T1499.004
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jun 14, 2022CVE 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

Compare your product and version with the public record. A matching version still requires validation against your environment.

Is a vulnerable build present?

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

  1. Affected versionversion=All versions < V6.5

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Siemens · SCALANCE XR526-8C, 2x230Vversion=All versions < V6.5
Siemens · SCALANCE XR524-8C, 1x230Vversion=All versions < V6.5
Siemens · SCALANCE XR528-6M (L3 int.)version=All versions < V6.5
Siemens · SCALANCE XR526-8C, 1x230V (L3 int.)version=All versions < V6.5
Siemens · SCALANCE XM416-4Cversion=All versions < V6.5
Siemens · SCALANCE XR526-8C, 2x230V (L3 int.)version=All versions < V6.5
Siemens · SCALANCE XR524-8C, 2x230Vversion=All versions < V6.5
Siemens · SCALANCE XR552-12M (2HR2)version=All versions < V6.5
Siemens · SCALANCE XR524-8C, 1x230V (L3 int.)version=All versions < V6.5
Siemens · SCALANCE XR528-6M (2HR2)version=All versions < V6.5
Siemens · SCALANCE XR528-6Mversion=All versions < V6.5
Siemens · SCALANCE XM408-4C (L3 int.)version=All versions < V6.5
Siemens · SCALANCE XM408-8C (L3 int.)version=All versions < V6.5
Siemens · SCALANCE XR526-8C, 24V (L3 int.)version=All versions < V6.5
Siemens · SCALANCE XR526-8C, 1x230Vversion=All versions < V6.5
Siemens · SCALANCE XR524-8C, 24Vversion=All versions < V6.5
Siemens · SCALANCE XR552-12M (2HR2, L3 int.)version=All versions < V6.5
Siemens · SCALANCE XM416-4C (L3 int.)version=All versions < V6.5
Siemens · SCALANCE XR526-8C, 24Vversion=All versions < V6.5
Siemens · SCALANCE XR524-8C, 2x230V (L3 int.)version=All versions < V6.5
Siemens · SCALANCE XM408-8Cversion=All versions < V6.5
Siemens · SCALANCE XR528-6M (2HR2, L3 int.)version=All versions < V6.5
Siemens · SCALANCE XM408-4Cversion=All versions < V6.5
Siemens · SCALANCE XR524-8C, 24V (L3 int.)version=All versions < V6.5
Siemens · SCALANCE XR552-12Mversion=All versions < V6.5

Published CVSS scores

5.9Siemens ProductCERTCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H
4.3NIST NVDAV:N/AC:M/Au:N/C:N/I:N/A:P
7.5NIST NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

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-354Improper Validation of Integrity Check Value
T1499.004Application or System Exploitation

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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