Cyber Resilience

CVE-2026-41502

Memory Safety in Bacnetstack Bacnet Stack 1.4.0 – 1.4.3

Public PoCMemory Safety
Published
24 April 2026
Modified
28 April 2026
Patch / advisory
CVSS Score v4 8.7
Click a component to see what it means
Raw vectorCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
EPSS Score 0.0040 33th percentile
Risk Priority 44 floored blend · peak EPSS

Summary

CVE-2026-41502 is a high-severity Out-of-bounds Read (CWE-125) vulnerability in Bacnetstack Bacnet Stack. Its CVSS base score is 8.7 (High).

Operationally, exploitation aligns with the MITRE ATT&CK technique Exploitation for Privilege Escalation (T1068); ranked at the 33th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog; a public proof-of-concept is referenced.

The strongest mitigations our analysis identified map to SA-11 (Developer Testing and Evaluation) and SA-15 (Development Process, Standards, and Tools) — see the control section below for these in your framework.

Deeper analysis AI-assisted summary

Synthesised by an AI model from the NVD description and linked references — a reading aid, not an authoritative source.

CVE-2026-41502 is an off-by-one out-of-bounds read vulnerability in the BACnet Stack, an open-source C library protocol stack for embedded systems implementing the BACnet protocol. The issue resides in the ReadPropertyMultiple (RPM) service decoder, specifically the rpm_decode_object_id() function in src/bacnet/rpm.c. Prior to version 1.4.3, the function checks if apdu_len is less than 5 but then accesses six byte positions (indices 0-5), including a context tag, four bytes for the object ID, and apdu[5] for an opening tag check. A crafted five-byte input passes the length check but triggers a one-byte read past the allocated buffer boundary. This affects any deployment enabling the ReadPropertyMultiple confirmed service handler, which is enabled by default in the reference server.

Unauthenticated remote attackers can exploit this vulnerability over the network by sending a specially crafted RPM request with a truncated object identifier. Successful exploitation causes a one-byte out-of-bounds read, which can lead to crashes or denial-of-service on vulnerable embedded BACnet devices. The CVSS v3.1 base score of 7.5 (AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H) reflects high availability impact with no confidentiality or integrity effects, mapped to CWE-125 (Out-of-bounds Read) and CWE-193 (Off-by-one Error).

The vulnerability is fixed in BACnet Stack version 1.4.3. Security practitioners should update to this version or later. Additional details are available in the GitHub Security Advisory at https://github.com/bacnet-stack/bacnet-stack/security/advisories/GHSA-7545-3fpx-4xw3.

EU & UK References

Vulnerability Data

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…

more

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.

CWE(s)

Related Threats

MITRE ATT&CK Enterprise Techniques

T1068 Exploitation for Privilege Escalation Privilege Escalation
Adversaries may exploit software vulnerabilities in an attempt to elevate privileges.
T1190 Exploit Public-Facing Application Initial Access
Adversaries may attempt to exploit a weakness in an Internet-facing host or system to initially access a network.
T1203 Exploitation for Client Execution Execution
Adversaries may exploit software vulnerabilities in client applications to execute code.
T1210 Exploitation of Remote Services Lateral Movement
Adversaries may exploit remote services to gain unauthorized access to internal systems once inside of a network.
T1211 Exploitation for Stealth Stealth
Adversaries may exploit vulnerabilities to evade detection by hiding activity, suppressing logging, or operating within trusted or unmonitored components.
T1212 Exploitation for Credential Access Credential Access
Adversaries may exploit software vulnerabilities in an attempt to collect credentials.
Derived from this CVE’s CWE(s) via the direct CWE→ATT&CK cross-walk.

CVEs Like This One

CVE-2026-26264Same product: Bacnetstack Bacnet Stack
CVE-2026-41503Same product: Bacnetstack Bacnet Stack
CVE-2025-66624Same product: Bacnetstack Bacnet Stack
CVE-2026-41475Same product: Bacnetstack Bacnet Stack
CVE-2026-21870Same product: Bacnetstack Bacnet Stack
CVE-2026-40279Same product: Bacnetstack Bacnet Stack
CVE-2026-21878Same product: Bacnetstack Bacnet Stack
CVE-2023-51773Same product: Bacnetstack Bacnet Stack
CVE-2023-30546Shared CWE-125, CWE-193
CVE-2026-45358Shared CWE-125, CWE-193

Affected Assets

bacnetstack
bacnet stack
1.5.0 · 1.4.0 — 1.4.3

Mitigating Controls

Control response

Prevent
Stop it (NIST 800-53)

Detect
Catch it (NIST detect / respond)

Harden
Shrink the surface (DISA STIG)

Validate
Prove the fix (OWASP ASVS)
  • V6.2.1

Mitigating Controls (NIST 800-53 r5) AI

Developer testing and evaluation directly finds out-of-bounds read flaws through static analysis, fuzzing, and dynamic bounds checks.

Requiring documented development standards and tools can embed bounds-checking and arithmetic-correctness rules that stop off-by-one mistakes at introduction.

Secure engineering principles require bounds checking and memory-safe constructs that stop out-of-bounds reads from being introduced.

Process isolation confines the effects of an out-of-bounds read to the compromised process.

Input validation rejects malformed indices or lengths that would otherwise cause reads outside buffer bounds.

Mitigating Controls (NIST CSF 2.0) AI

Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→CSF cross-walk (authority under review) — links open the control.

PR.PS-06 mostly match
prevents

Secure-development practices such as bounds checking and memory-safe languages directly prevent out-of-bounds reads.

ID.RA-01 partial match
prevents

Vulnerability scanning and recording can discover instances of out-of-bounds reads after code is deployed.

PR.PS-02 partial match
prevents

Routine patching replaces vulnerable code containing out-of-bounds read flaws.

Mitigating Controls (ISO/IEC 27001:2022 Annex A) AI

Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→ISO cross-walk (authority under review) — links open the control.

finds

Security testing in development and acceptance includes fuzzing and static analysis that detect out-of-bounds read defects before release.

A.8.15 Logging partial match
finds

Logging can record evidence of an out-of-bounds read but does not prevent the weakness itself.

prevents

Secure development life cycle mandates input validation and bounds checking that directly prevent out-of-bounds reads.

prevents

Application security requirements include explicit bounds and memory-safety specifications that mitigate buffer over-reads.

prevents

Secure system architecture and engineering principles require memory-safe design patterns and runtime protections against out-of-bounds access.

prevents

Secure coding standards explicitly forbid unsafe pointer arithmetic and mandate bounds-checked reads, eliminating CWE-125.

References