CVE-2026-41503Public exploitNetwork attack vector

Remote device crash via unchecked extended-tag parsing

Published Apr 24, 2026 · Updated Apr 24, 2026

Out-of-bounds read in BACnet Stack allows remote attackers to crash devices via a truncated ReadPropertyMultiple request. rpm_decode_object_property() passes a one-byte extended-tag payload to decode_tag_number_and_value(), which reads apdu[1] before checking the remaining length. The handler is enabled by default in the reference server, exposing affected 1.4.0 through 1.4.2 and 1.5.0.rc1 builds to one-packet service interruption.

CVSS severity8.7
High
EPSS probability0.41%
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 BACnet Stack allows remote attackers to crash devices via a truncated ReadPropertyMultiple request. rpm_decode_object_property() passes a one-byte extended-tag payload to decode_tag_number_and_value(), which reads apdu[1] before checking the remaining length. The handler is enabled by default in the reference server, exposing affected 1.4.0 through 1.4.2 and 1.5.0.rc1 builds to one-packet service interruption.

The record

CVE
CVE-2026-41503
Published
Apr 24, 2026
Updated
Apr 24, 2026
Vendor
BACnet Stack
Product
BACnet Stack
Classifications
CWE-125, T0814
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Apr 24, 2026CVE publishedPublication date reported by the CVE source.
  2. Apr 24, 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=>= 1.4.0, < 1.4.3

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

BACnet Stack · BACnet Stackversion=>= 1.4.0, < 1.4.3

Published CVSS scores

8.7GitHub, Inc.CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N
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 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-125Out-of-bounds Read
T0814Denial of Service

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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