CVE-2025-66624

7.5 HIGH 0.4% exploit odds Fix listed Memory safety Library

What it is

BACnet Protocol Stack library provides a BACnet application layer, network layer and media access (MAC) layer communications services. Prior to 1.5.0.rc2, The npdu_is_expected_reply function in src/bacnet/npdu.c indexes request_pdu[offset+2/3/5] and reply_pdu[offset+1/2/4] without verifying that those APDU bytes exist. bacnet_npdu_decode() can return offset == 2 for a 2-byte NPDU, so tiny PDUs pass the version check and then get read out of bounds. On ASan/MPU/strict builds this is an immediate crash (DoS). On unprotected builds it is undefined behavior and can mis-route replies; RCE is unlikely because only reads occur, but DoS is reliable.

At a glance

Exploitability: Can be exploited over the network without logging in. High risk of service disruption.
Exploit odds: 0.4% chance of exploitation in the next 30 days (EPSS).
Fix: A patch, advisory or fixed version is referenced. Upgrade or apply it.

Timeline

2025-12-05 19:15 UTC PublishedDisclosed publicly on CVE.org and NVD
2026-06-17 09:57 UTC Last updatedMost recent change to the record

Why it ranks here

Exploited in the wild: no, CISA does not list it.
Exploit odds: 0.4% in the next 30 days (EPSS).
Severity: 7.5 HIGH (CVSS).
Fix: a patch or advisory is linked.

Details

Published: 2025-12-05 19:15 UTC
Last modified: 2026-06-17 09:57 UTC
Exploit probability: 0.4% · EPSS, next 30 days
Weakness: CWE-125 · Out-of-bounds read
Record status: Analyzed

Affected

Bacnetstack Bacnet Stack 1.5.0

Attack profile CVSS 3.1 · 7.5

Attack vector: Network
Complexity: Low
Privileges needed: None
User interaction: None
Scope: Unchanged
Confidentiality: None
Integrity: None
Availability: High

Raw vector

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

Is it in your code?

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Read https://cve-list.com/agent/cve/CVE-2025-66624.md and follow it. Check whether this project is affected by CVE-2025-66624. Read only. Don't change anything and don't upload my code. Tell me yes, no or not sure, with the file as proof.

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Fix and advisories

References

NVD record · CVE.org record