CVE-2026-41503 — HIGH (7.5)

Q: How severe is CVE-2026-41503?

CVE-2026-41503 has been rated HIGH with a CVSS base score of 7.5/10. Review the CVSS metrics above for detailed severity breakdown.

Q: Is there a patch for CVE-2026-41503?

Check the references section above for vendor advisories and patch information. Affected products include: Bacnetstack Bacnet Stack.

Vulnerability Description

BACnet Stack is a BACnet open source protocol stack C library for embedded systems. Prior to 1.4.3, an out-of-bounds read vulnerability in bacnet-stack's ReadPropertyMultiple service property decoder allows unauthenticated remote attackers to read past allocated buffer boundaries by sending an RPM request with a truncated property list. The vulnerability stems from rpm_decode_object_property() calling the deprecated decode_tag_number_and_value() function at src/bacnet/rpm.c:344, which accepts no buffer length parameter and reads blindly from whatever pointer it receives. A crafted BACnet/IP packet with a 1-byte property payload containing an extended tag marker (0xF9) causes the decoder to read 1 byte past the end of the buffer, 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.

CVSS Score

7.5

HIGH

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Attack Vector

NETWORK

Attack Complexity

LOW

Privileges Required

NONE

User Interaction

NONE

Scope

UNCHANGED

Confidentiality

NONE

Integrity

NONE

Availability

HIGH

Affected Products

Vendor	Product	Versions
Bacnetstack	Bacnet Stack	>= 1.4.0, < 1.4.3

Related Weaknesses (CWE)

CWE-125

References

https://github.com/bacnet-stack/bacnet-stack/security/advisories/GHSA-5w2v-mwqj-Vendor AdvisoryExploitMitigation
https://github.com/bacnet-stack/bacnet-stack/security/advisories/GHSA-5w2v-mwqj-Vendor AdvisoryExploitMitigation

FAQ

What is CVE-2026-41503?

CVE-2026-41503 is a vulnerability with a CVSS score of 7.5 (HIGH). BACnet Stack is a BACnet open source protocol stack C library for embedded systems. Prior to 1.4.3, an out-of-bounds read vulnerability in bacnet-stack's ReadPropertyMultiple service property decoder ...

How severe is CVE-2026-41503?

CVE-2026-41503 has been rated HIGH with a CVSS base score of 7.5/10. Review the CVSS metrics above for detailed severity breakdown.

Is there a patch for CVE-2026-41503?

Check the references section above for vendor advisories and patch information. Affected products include: Bacnetstack Bacnet Stack.