CVE-2020-36872Public exploitNetwork attack vector

Unauthenticated crash via malformed BVLC Length

Published Nov 26, 2025 · Updated Jul 28, 2026

Denial of service in BACnet Test Server 1.01 and earlier allows remote attackers to crash the application via a malformed BVLC Length field. The BACnet/IP BVLC packet handler trusts an inconsistent length value in a UDP frame, proceeds beyond the supplied packet data, and triggers an access violation. No authentication or user interaction is required; one crafted datagram sent to the listening service can interrupt the server process.

CVSS severity8.7
High
EPSS probability0.50%
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 BACnet Test Server 1.01 and earlier allows remote attackers to crash the application via a malformed BVLC Length field. The BACnet/IP BVLC packet handler trusts an inconsistent length value in a UDP frame, proceeds beyond the supplied packet data, and triggers an access violation. No authentication or user interaction is required; one crafted datagram sent to the listening service can interrupt the server process.

The record

CVE
CVE-2020-36872
Published
Nov 26, 2025
Updated
Jul 28, 2026
Vendor
BACnet Interoperability Testing Services, Inc.
Product
BACnet Test Server
Classifications
CWE-400, T1499.004
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Nov 26, 2025CVE publishedPublication date reported by the CVE source.
  2. Jul 28, 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?

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

  1. Affected versionversion=0 <=1.01

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

BACnet Interoperability Testing Services, Inc. · BACnet Test Serverversion=0 <=1.01

Published CVSS scores

8.7VulnCheckCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N

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.

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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 exploitPublished

Weakness, pattern, technique

CWE-400Uncontrolled Resource Consumption
T1499.004Application or System Exploitation

Public exploit references

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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