APOGEE MBC (PPC) (BACnet): Stack-based Buffer Overflow
CVE-2026-102076 is a high-severity stack-based buffer overflow vulnerability in APOGEE MBC (PPC) (BACnet) from Siemens, with a CVSS 3.1 base score of 7.5 out of 10. It can be exploited remotely over the network by an unauthenticated attacker, without any action from a user. Affected APOGEE MBC (PPC) (BACnet) versions: all versions. The record does not name a fixed version, so check the vendor advisory. There is no confirmed exploitation so far. EPSS estimates a 0.42% chance of exploitation within 30 days, which is low compared with other CVEs.
High severity with no evidence of exploitation so far.
What to do
- Update APOGEE PXC Compact (BACnet) to V3.5.7 or a later version.
- Update APOGEE PXC Compact (P2 Ethernet) to V2.8.21 or a later version.
- Update APOGEE PXC Modular (BACnet) to V3.5.7 or a later version.
- Until you can update, restrict network access to the affected service so it is not reachable from untrusted networks.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| Siemens | APOGEE MBC (PPC) (BACnet) | all versions | Not stated |
| Siemens | APOGEE MBC (PPC) (P2 Ethernet) | all versions | Not stated |
| Siemens | APOGEE MEC (PPC) (BACnet) | all versions | Not stated |
| Siemens | APOGEE MEC (PPC) (P2 Ethernet) | all versions | Not stated |
| Siemens | APOGEE PXC Compact (BACnet) | before V3.5.7 | V3.5.7 |
| Siemens | APOGEE PXC Compact (P2 Ethernet) | before V2.8.21 | V2.8.21 |
| Siemens | APOGEE PXC Modular (BACnet) | before V3.5.7 | V3.5.7 |
| Siemens | APOGEE PXC Modular (P2 Ethernet) | before V2.8.21 | V2.8.21 |
| Siemens | TALON TC Compact (BACnet) | before V3.5.7 | V3.5.7 |
| Siemens | TALON TC Modular (BACnet) | before V3.5.7 | V3.5.7 |
Version data comes from the organisation that assigned the CVE. Confirm against the vendor advisory before deciding you are unaffected.
How the severity score breaks down
- Attack vector
- NetworkCan be exploited remotely over a network, including the internet.
- Attack complexity
- LowNo special conditions are needed; the attack works reliably.
- Privileges required
- NoneNo account or login is needed.
- User interaction
- NoneNo action by a victim is required.
- Scope
- UnchangedImpact stays within the vulnerable component.
- Confidentiality
- NoneNo data is disclosed.
- Integrity
- NoneNothing can be modified.
- Availability
- HighThe component can be taken down completely.
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H. Scored by CNA (siemens.com).
| Scoring system | Score | Severity | Scored by |
|---|---|---|---|
| CVSS 4.0 | 8.7 | High | CNA (siemens.com) |
| CVSS 3.1 | 7.5 | High | CNA (siemens.com) |
Official description
A vulnerability has been identified in APOGEE MBC (PPC) (BACnet) (All versions), APOGEE MBC (PPC) (P2 Ethernet) (All versions), APOGEE MEC (PPC) (BACnet) (All versions), APOGEE MEC (PPC) (P2 Ethernet) (All versions), APOGEE PXC Compact (BACnet) (All versions < V3.5.7), APOGEE PXC Compact (P2 Ethernet) (All versions < V2.8.21), APOGEE PXC Modular (BACnet) (All versions < V3.5.7), APOGEE PXC Modular (P2 Ethernet) (All versions < V2.8.21), TALON TC Compact (BACnet) (All versions < V3.5.7), TALON TC Modular (BACnet) (All versions < V3.5.7). The affected product web service does not properly validate user-supplied input in upload code. This could allow an unauthenticated remote attacker to cause a denial of service.
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Stack-based Buffer Overflow
The product writes past the end of a buffer that was allocated on the stack.
How developers prevent this class of flaw
- Use automatic buffer overflow detection mechanisms that are offered by certain compilers or compiler extensions. Examples include: the Microsoft Visual Studio /GS flag, Fedora/Red Hat FORTIFY_SOURCE GCC flag, StackGuard, and ProPolice, which provide various mechanisms including canary-based detection and range/index checking. D3-SFCV (Stack Frame Canary Validation) from D3FEND discusses canary-based detection in detail.
- Use an abstraction library to abstract away risky APIs. Not a complete solution.
- Implement and perform bounds checking on input.
Timeline
- CVE record published.
- CISA published its SSVC assessment (exploitation: none, automatable: yes, technical impact: partial).
- Record last changed materially (score, affected products, status or references).
References
Other references
Other vulnerabilities in APOGEE MBC (PPC) (BACnet)
- 7.5 High severity
- 7.5 High severity
- 8.2 High severity
- 7.5 High severity
Recent Stack-based Buffer Overflow vulnerabilities
- 7.8 High severity
- 7.8 High severity
- 7.8 High severity
- 7.8 High severity
- 7.1 High severity
- 7.3 High severity
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