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TI-2025-27049 Aliases CVE-2025-40556GHSA-c7rq-qv3j-63j3

Improper input validation in Siemens BACnet ATEC 550-440

Priority LOW 31CWE-20Published · Updated

Key facts

Attack vector
Adjacent network
Privileges required
None
User interaction
None
Attack complexity
Low
Attack requirements
None
Impact type
—
Confidentiality · integrity · availability
None · None · High
Fix status
No fix listed

Attack profile from CVSS 4.0 · CNA. Fix status from CNA.

Summary

A vulnerability has been identified in BACnet ATEC 550-440 (All versions), BACnet ATEC 550-441 (All versions), BACnet ATEC 550-445 (All versions), BACnet ATEC 550-446 (All versions). Affected devices improperly handle specific incoming BACnet MSTP messages. This could allow an attacker residing in the same BACnet network to send a specially crafted MSTP message that results in a denial of service condition of the targeted device. A power cycle is required to restore the device's normal operation.

Why it matters now

Exploitation None reported CISA SSVC · not in CISA KEV
EPSS 0.00251 16th percentileScored 2026-11-07
Fix No fix listed No fixed version in the sources yet

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation
None
Automatable
No
Technical impact
Partial

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

VendorProductAffected versionsFixed inStatusSource
SiemensBACnet ATEC 550-440all versions—No fix listedCNA
SiemensBACnet ATEC 550-441all versions—No fix listedCNA
SiemensBACnet ATEC 550-445all versions—No fix listedCNA
SiemensBACnet ATEC 550-446all versions—No fix listedCNA
  • BACnet ATEC 550-440 VendorSiemens Affected all versions Fixed in — No fix listed CNA
  • BACnet ATEC 550-441 VendorSiemens Affected all versions Fixed in — No fix listed CNA
  • BACnet ATEC 550-445 VendorSiemens Affected all versions Fixed in — No fix listed CNA
  • BACnet ATEC 550-446 VendorSiemens Affected all versions Fixed in — No fix listed CNA

Remediation

No fixed version listed by the sources yet.

Timeline

  1. 2026-10-02 Threatist record created from CVE-2025-40556
  2. 2026-10-03 Alias added: GHSA-c7rq-qv3j-63j3

References

Other 1

  • TI-2026-20057 Authentication bypass in Fortinet FortiWeb KEVCVSS 3.1CRITICAL 9.4
  • TI-2025-26358 tls: fix handling of zero-length records on the rx_list KEVCVSS 3.1CRITICAL 9.8
  • TI-2025-18911 Heap-based buffer overflow in Fortinet FortiSwitchManager KEVCVSS 3.1CRITICAL 9.8
  • TI-2025-09686 Type confusion in Google Chrome KEVCVSS 3.1CRITICAL 9.8
  • TI-2022-07142 Code injection in Spring Framework KEVCVSS 3.1CRITICAL 9.8
  • TI-2021-19919 Apache Log4j2 JNDI features do not protect against attacker controlled LDAP and other JNDI related endpoints KEVCVSS 3.1CRITICAL 10.0
See all 2487 →

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences