CVE-2020-27737
A vulnerability has been identified in Nucleus 4 (All versions < V4.1.0), Nucleus NET (All...
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), Nucleus ReadyStart V3 (All versions < V2017.02.3), Nucleus ReadyStart V4 (All versions < V4.1.0), Nucleus Source Code (Versions including affected DNS modules), SIMOTICS CONNECT 400 (All versions < V0.5.0.0), TALON TC Compact (BACnet) (All versions < V3.5.5), TALON TC Modular (BACnet) (All versions < V3.5.5). The DNS response parsing functionality does not properly validate various length and counts of the records. The parsing of malformed responses could result in a read past the end of an allocated structure. An attacker with a privileged position in the network could leverage this vulnerability to cause a denial-of-service condition or leak the memory past the allocated structure.
Attack profile
How easy it is to exploit
- Attack vector
- Network
- Complexity
- High
- Privileges needed
- None
- User interaction
- None
What an attacker can affect
- Confidentiality
- Low
- Integrity
- None
- Availability
- High
Exploit likelihood
What each source reports
CVE List Score used
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), Nucleus ReadyStart V3 (All versions < V2017.02.3), Nucleus ReadyStart V4 (All versions < V4.1.0), Nucleus Source Code (Versions including affected DNS modules), SIMOTICS CONNECT 400 (All versions < V0.5.0.0), TALON TC Compact (BACnet) (All versions < V3.5.5), TALON TC Modular (BACnet) (All versions < V3.5.5). The DNS response parsing functionality does not properly validate various length and counts of the records. The parsing of malformed responses could result in a read past the end of an allocated structure. An attacker with a privileged position in the network could leverage this vulnerability to cause a denial-of-service condition or leak the memory past the allocated structure.
- Record
CVE-2020-27737- CVSS 3.1
- 6.5 Medium
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:H/E:P/RL:O/RC:C - Weakness
- CWE-125
- Updated
- 2026-11-02
EUVDEUVD-2020-20241
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), Nucleus ReadyStart V3 (All versions < V2017.02.3), Nucleus ReadyStart V4 (All versions < V4.1.0), Nucleus Source Code (Versions including affected DNS modules), SIMOTICS CONNECT 400 (All versions < V0.5.0.0), TALON TC Compact (BACnet) (All versions < V3.5.5), TALON TC Modular (BACnet) (All versions < V3.5.5). The DNS response parsing functionality does not properly validate various length and counts of the records. The parsing of malformed responses could result in a read past the end of an allocated structure. An attacker with a privileged position in the network could leverage this vulnerability to cause a denial-of-service condition or leak the memory past the allocated structure.
- Record
EUVD-2020-20241- CVSS 3.1
- 6.5 Medium
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:H/E:P/RL:O/RC:C - Updated
- 2026-11-03
GitHub AdvisoriesGHSA-j94w-w786-mv9m
A vulnerability has been identified in Nucleus 4 (All versions < V4.1.0), Nucleus NET (All...
A vulnerability has been identified in Nucleus 4 (All versions < V4.1.0), Nucleus NET (All versions), Nucleus RTOS (versions including affected DNS modules), Nucleus ReadyStart (All versions < V2017.02.3), Nucleus Source Code (versions including affected DNS modules), SIMOTICS CONNECT 400 (All versions < V0.5.0.0), VSTAR (versions including affected DNS modules). The DNS response parsing functionality does not properly validate various length and counts of the records. The parsing of malformed responses could result in a read past the end of an allocated structure. An attacker with a privileged position in the network could leverage this vulnerability to cause a denial-of-service condition or leak the memory past the allocated structure.
- Record
GHSA-j94w-w786-mv9m- CVSS 3.1
- 6.5 Medium
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:H - Weakness
- CWE-125
- Updated
- 2026-11-02
NVD
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), Nucleus ReadyStart V3 (All versions < V2017.02.3), Nucleus ReadyStart V4 (All versions < V4.1.0), Nucleus Source Code (Versions including affected DNS modules), SIMOTICS CONNECT 400 (All versions < V0.5.0.0), TALON TC Compact (BACnet) (All versions < V3.5.5), TALON TC Modular (BACnet) (All versions < V3.5.5). The DNS response parsing functionality does not properly validate various length and counts of the records. The parsing of malformed responses could result in a read past the end of an allocated structure. An attacker with a privileged position in the network could leverage this vulnerability to cause a denial-of-service condition or leak the memory past the allocated structure.
- Record
CVE-2020-27737- CVSS 3.1
- 6.5 Medium
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:H - CVSS 2.0
- 5.8 Medium
AV:N/AC:M/Au:N/C:P/I:N/A:P - Weakness
- CWE-125
- Updated
- 2026-11-02
Affected products
- siemens apogee pxc compact (bacnet)
- siemens apogee pxc compact (p2 ethernet)
- siemens apogee pxc modular (bacnet)
- siemens apogee pxc modular (p2 ethernet)
- siemens nucleus net
- siemens nucleus readystart v3
- siemens nucleus readystart v4
- siemens nucleus source code
- siemens simotics connect 400
- siemens talon tc compact (bacnet)
- siemens talon tc modular (bacnet)
- siemens simotics connect 400 firmware
History
| Recorded | Changed | Sources |
|---|---|---|
| aliases | EUVD | |
| first indexed | CVE List, GitHub Advisories, NVD |
Dates are when Every CVE recorded each change. Upstream dates may differ.
In short
CVE-2020-27737 is a medium vulnerability (CVSS 6.5) in Siemens Apogee Pxc Compact (bacnet), published April 22, 2021. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 3.57%, the 89th percentile. No source names a fixed version.