{"cve":"CVE-2020-27738","nvd":{"published":"2021-04-22T21:15:09.313","modified":"2026-06-17T03:09:32.927","status":"Modified","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.","cvss_v4":null,"cvss_v3":{"version":"3.1","vector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:H","score":7.4},"cwes":["CWE-119","CWE-788"],"references":["https://cert-portal.siemens.com/productcert/pdf/ssa-180579.pdf","https://cert-portal.siemens.com/productcert/pdf/ssa-669158.pdf","https://cert-portal.siemens.com/productcert/pdf/ssa-705111.pdf","https://cert-portal.siemens.com/productcert/pdf/ssa-180579.pdf","https://cert-portal.siemens.com/productcert/pdf/ssa-669158.pdf"],"products":["siemens:nucleus_net","siemens:nucleus_readystart_v3","siemens:nucleus_readystart_v4","siemens:nucleus_source_code","siemens:simotics_connect_400_firmware"],"source":"nvd","synced_at":"2026-10-19T21:17:01.373894544+00:00"},"epss":{"cve":"CVE-2020-27738","score":0.03659,"percentile":0.89626,"date":"2026-11-01"},"kev":null,"osv":[],"attribution":["This product uses the NVD API but is not endorsed or certified by the NVD.","EPSS scores: FIRST Exploit Prediction Scoring System, https://www.first.org/epss","Known exploited vulnerabilities: CISA Known Exploited Vulnerabilities Catalog, https://www.cisa.gov/known-exploited-vulnerabilities-catalog","Package advisories: OSV (https://osv.dev), from the GitHub Advisory Database, PyPA, Go, RustSec and other ecosystem databases, under CC-BY 4.0 or CC0","CVE records: the CVE Program's CVE List (https://www.cve.org), under its terms of use (https://www.cve.org/Legal/TermsOfUse). CVE is a registered trademark of The MITRE Corporation; this product is not affiliated with the CVE Program."]}