Vulnerability · Published Apr 22, 2021 · Assigned by siemens

CVE-2020-27738

Medium 6.5

In plain English

A medium-severity security flaw in APOGEE PXC Compact (BACnet) from Siemens. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 3.7% (higher than 90% of all known vulnerabilities).

Severity (CVSS 3.1)6.5Medium
Exploit odds (30 days)3.7%top 10.3% of all CVEs
Exploited in the wildNo reportsnot in CISA KEV
Attack toolingNoneno public tooling known

Official 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), 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 domain name record decompression functionality does not properly validate the pointer offset values. The parsing of malformed responses could result in a read access 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.

Affected products (as reported)

VendorProductVersions
Siemens APOGEE PXC Compact (BACnet) All versions < V3.5.5
Siemens APOGEE PXC Compact (P2 Ethernet) All versions < V2.8.20
Siemens APOGEE PXC Modular (BACnet) All versions < V3.5.5
Siemens APOGEE PXC Modular (P2 Ethernet) All versions < V2.8.20
Siemens Nucleus NET All versions
Siemens Nucleus ReadyStart V3 All versions < V2017.02.3
Siemens Nucleus ReadyStart V4 All versions < V4.1.0
Siemens Nucleus Source Code Versions including affected DNS modules
Siemens SIMOTICS CONNECT 400 All versions < V0.5.0.0
Siemens TALON TC Compact (BACnet) All versions < V3.5.5
Siemens TALON TC Modular (BACnet) All versions < V3.5.5

Weakness: CWE-788 · Vector: 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

References