CVE-2020-28388: A vulnerability has been identified in APOGEE PXC Compact (BACnet) (All versions < V3.5.5), APOGEE PXC Compact (P2 Ethernet) (All versions < V2.8.20),...

Description

A vulnerability has been identified in APOGEE PXC Compact (BACnet) (All versions < V3.5.5), APOGEE PXC Compact (P2 Ethernet) (All versions < V2.8.20), APOGEE PXC Modular (BACnet) (All versions < V3.5.5), APOGEE PXC Modular (P2 Ethernet) (All versions < V2.8.20), Nucleus NET (All versions < V5.2), Nucleus ReadyStart V3 (All versions < V2012.12), Nucleus Source Code (All versions), PLUSCONTROL 1st Gen (All versions), TALON TC Compact (BACnet) (All versions < V3.5.5), TALON TC Modular (BACnet) (All versions < V3.5.5). Initial Sequence Numbers (ISNs) for TCP connections are derived from an insufficiently random source. As a result, the ISN of current and future TCP connections could be predictable. An attacker could hijack existing sessions or spoof future ones.

Metrics

CVSS 3.1

5.3/10

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

EPSS Probability

1.55%

72.0th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

CWE-342

Affected Software

Vendor	Product	Versions
Siemens	Capital Vstar	All versions
Siemens	Nucleus Net	< 5.2
Siemens	Nucleus Source Code	All versions
Siemens	Pluscontrol 1st Gen	All versions
Siemens	Nucleus Readystart	< 2012.12

References

Timeline

Published: Feb 9, 2021
Last Modified: Jun 17, 2026
Status: Modified

Frequently Asked Questions

What is CVE-2020-28388?

A vulnerability has been identified in APOGEE PXC Compact (BACnet) (All versions < V3.5.5), APOGEE PXC Compact (P2 Ethernet) (All versions < V2.8.20), APOGEE PXC Modular (BACnet) (All versions < V3.5.5), APOGEE PXC Modular (P2 Ethernet) (All versions < V2.8.20), Nucleus NET (All versions < V5.2), Nucleus ReadyStart V3 (All versions < V2012.12), Nucleus Source Code (All versions), PLUSCONTROL 1st Gen (All versions), TALON TC Compact (BACnet) (All versions < V3.5.5), TALON TC Modular (BACnet) (All versions < V3.5.5). Initial Sequence Numbers (ISNs) for TCP connections are derived from an insufficiently random source. As a result, the ISN of current and future TCP connections could be predictable. An attacker could hijack existing sessions or spoof future ones.

How severe is CVE-2020-28388?

CVE-2020-28388 has a CVSS score of 5.3/10 (MEDIUM severity). The EPSS model estimates a 1.55% probability of exploitation in the next 30 days.

How do I fix CVE-2020-28388?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.