CVE-2026-41502

BACnet Stack: Off-by-One Out-of-Bounds Read in ReadPropertyMultiple Object ID Decoder

HIGH
7.5
CVSS Score
Published: April 24, 2026 at 07:40 PM UTC
Updated: June 17, 2026 at 10:46 AM UTC
1 product affected across 1 vendorBacnet Stack

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Severity
HIGH7.5
Exploit prediction
EPSS 0.4%
SSVC
PoC

Description

BACnet Stack is a BACnet open source protocol stack C library for embedded systems. Prior to 1.4.3, an off-by-one out-of-bounds read vulnerability in bacnet-stack's ReadPropertyMultiple service decoder allows unauthenticated remote attackers to read one byte past an allocated buffer boundary by sending a crafted RPM request with a truncated object identifier. The vulnerability is in rpm_decode_object_id(), which checks apdu_len < 5 but then accesses all 6 byte positions (indices 0-5) — consuming 1 byte for the context tag, 4 bytes for the object ID, then reading apdu[5] for the opening tag check. A 5-byte input passes the length check but causes a 1-byte OOB read, leading to crashes on embedded BACnet devices. The vulnerability exists in src/bacnet/rpm.c and affects any deployment that enables the ReadPropertyMultiple confirmed service handler (enabled by default in the reference server). This vulnerability is fixed in 1.4.3.

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

v < 1.4.31.4.0 ≤ v < 1.4.31.5.0 rc11.5.0 rc21.5.0 rc3
Affected range stops below 1.4.3, so it looks safe — our inference, not a vendor statement

Remediation

No guide yet

No remediation guidance has been written for this CVE yet. What the record does show:

References (1)

x_refsource_CONFIRMExploitMitigationVendor Advisory
Source: cverecord
https://github.com/bacnet-stack/bacnet-stack/security/advisories/GHSA-7545-3fpx-4xw3

SSVC — Action Prioritization

SSVCPoCAutomatablePartial impact

SSVC signals action urgency (what to patch first), separate from CVSS which measures severity.

CVSS

Attack Vector
NETWORK
Complexity
LOW
Privileges
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality
NONE
Integrity
NONE
Availability
HIGH
Vector?

Quick Info

StatusANALYZED
CWE
CWE-125CWE-193

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