CVE-2025-66624Public exploitNetwork attack vector

Remote service crash via unchecked APDU indexing

Published Dec 5, 2025 · Updated Dec 8, 2025

Out-of-bounds read in BACnet Stack before 1.5.0.rc2 allows remote attackers to crash strict builds via a malformed MS/TP frame. The npdu_is_expected_reply function indexes request and reply APDU bytes after a two-byte NPDU passes decoding, without checking that the indexed offsets exist. Reachability requires MS/TP traffic and a queued confirmed-service reply; strict builds abort, while unprotected builds can misroute replies.

CVSS severity7.5
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 before 1.5.0.rc2 allows remote attackers to crash strict builds via a malformed MS/TP frame. The npdu_is_expected_reply function indexes request and reply APDU bytes after a two-byte NPDU passes decoding, without checking that the indexed offsets exist. Reachability requires MS/TP traffic and a queued confirmed-service reply; strict builds abort, while unprotected builds can misroute replies.

The record

CVE
CVE-2025-66624
Published
Dec 5, 2025
Updated
Dec 8, 2025
Vendor
BACnet Stack
Product
BACnet Stack
Classifications
CWE-125, T1499
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Dec 5, 2025CVE publishedPublication date reported by the CVE source.
  2. Dec 8, 2025Record 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=< 1.5.0.rc2

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

BACnet Stack · BACnet Stackversion=< 1.5.0.rc2

Published CVSS scores

7.5GitHub, Inc.CVSS: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 exploitPublished

Weakness, pattern, technique

CWE-125Out-of-bounds Read
T1499Endpoint Denial 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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