CVE-2026-26264Network attack vector

Unauthenticated service crash via WriteProperty length underflow

Published Feb 13, 2026 · Updated Feb 13, 2026

Out-of-bounds read in BACnet Stack before 1.4.3rc2 and 1.5.0rc1 through 1.5.0rc3 allows remote attackers to crash services. In wp_decode_service_request, the optional priority-tag path passes apdu_len minus apdu_size as the remaining length, so a truncated WriteProperty APDU underflows the size supplied to bacnet_unsigned_context_decode. Any BACnet service that accepts WriteProperty requests exposes the decoder; a malformed or truncated APDU causes a process crash or instability.

CVSS severity8.1
High
EPSS probability0.38%
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 1.4.3rc2 and 1.5.0rc1 through 1.5.0rc3 allows remote attackers to crash services. In wp_decode_service_request, the optional priority-tag path passes apdu_len minus apdu_size as the remaining length, so a truncated WriteProperty APDU underflows the size supplied to bacnet_unsigned_context_decode. Any BACnet service that accepts WriteProperty requests exposes the decoder; a malformed or truncated APDU causes a process crash or instability.

The record

CVE
CVE-2026-26264
Published
Feb 13, 2026
Updated
Feb 13, 2026
Vendor
BACnet Stack
Product
BACnet Stack
Classifications
CWE-125, T1499
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Feb 13, 2026CVE publishedPublication date reported by the CVE source.
  2. Feb 13, 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=< 1.4.3rc2
  2. Affected versionversion=>= 1.5.0rc1, < 1.5.0rc4

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

BACnet Stack · BACnet Stackversion=< 1.4.3rc2; version=>= 1.5.0rc1, < 1.5.0rc4

Published CVSS scores

8.1NISTCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H
7.8GitHubCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:N/VA:H/SC:N/SI:N/SA:N/E: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.

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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 exploitUnconfirmed

Weakness, pattern, technique

CWE-125Out-of-bounds Read
T1499Endpoint Denial of Service

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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