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.
CVSS v4.0 Metrics
Exploitability
Attack VectorNetwork
ComplexityLow
RequirementsPresent
PrivilegesNone
User InteractionNone
Threat
Exploit MaturityPoC
Vulnerable System
ConfidentialityNone
IntegrityLow
AvailabilityLow
Subsequent System
ConfidentialityNone
IntegrityNone
AvailabilityNone
Supplemental
SafetyNegligible
AutomatableYes
RecoveryAutomatic
Value DensityConcentrated
UrgencyMedium
Change Log
| Date | Source | Changes | Score |
|---|
| 2026-07-21 | cve.org | initial, patch: Unavailable | 2.9 |
Affected Software
| Vendor | Product | Version |
|---|
| Siemens | APOGEE PXC Compact (BACnet) | < 3.5.5 |
| Siemens | APOGEE PXC Compact (P2 Ethernet) | < 2.8.20 |
| Siemens | APOGEE PXC Modular (BACnet) | < 3.5.5 |
| Siemens | APOGEE PXC Modular (P2 Ethernet) | < 2.8.20 |
| siemens | capital_vstar | All versions |
| Siemens | Nucleus NET | < 5.2 |
| Siemens | Nucleus ReadyStart V3 | < 2012.12 |
| Siemens | Nucleus Source Code | All versions |
| siemens | nucleus_net | < 5.2 |
| siemens | nucleus_readystart | < 2012.12 |
| siemens | nucleus_source_code | All versions |
| Siemens | PLUSCONTROL 1st Gen | All versions |
| siemens | pluscontrol_1st_gen | All versions |
| Siemens | TALON TC Compact (BACnet) | < 3.5.5 |
| Siemens | TALON TC Modular (BACnet) | < 3.5.5 |
Published: 2021-02-09
