{"cve":"CVE-2021-31887","nvd":{"published":"2021-11-09T12:15:09.587","modified":"2026-06-17T03:52:25.500","status":"Modified","description":"A vulnerability has been identified in APOGEE MBC (PPC) (BACnet) (All versions), APOGEE MBC (PPC) (P2 Ethernet) (All versions), APOGEE MEC (PPC) (BACnet) (All versions), APOGEE MEC (PPC) (P2 Ethernet) (All versions), APOGEE PXC Compact (BACnet) (All versions < V3.5.4), APOGEE PXC Compact (P2 Ethernet) (All versions < V2.8.19), APOGEE PXC Modular (BACnet) (All versions < V3.5.4), APOGEE PXC Modular (P2 Ethernet) (All versions < V2.8.19), Desigo PXC00-E.D (All versions >= V2.3 and < V6.30.016), Desigo PXC00-U (All versions >= V2.3 and < V6.30.016), Desigo PXC001-E.D (All versions >= V2.3 and < V6.30.016), Desigo PXC100-E.D (All versions >= V2.3 and < V6.30.016), Desigo PXC12-E.D (All versions >= V2.3 and < V6.30.016), Desigo PXC128-U (All versions >= V2.3 and < V6.30.016), Desigo PXC200-E.D (All versions >= V2.3 and < V6.30.016), Desigo PXC22-E.D (All versions >= V2.3 and < V6.30.016), Desigo PXC22.1-E.D (All versions >= V2.3 and < V6.30.016), Desigo PXC36.1-E.D (All versions >= V2.3 and < V6.30.016), Desigo PXC50-E.D (All versions >= V2.3 and < V6.30.016), Desigo PXC64-U (All versions >= V2.3 and < V6.30.016), Desigo PXM20-E (All versions >= V2.3 and < V6.30.016), Nucleus NET (All versions), Nucleus ReadyStart V3 (All versions < V2017.02.4), Nucleus Source Code (All versions), TALON TC Compact (BACnet) (All versions < V3.5.4), TALON TC Modular (BACnet) (All versions < V3.5.4). FTP server does not properly validate the length of the “PWD/XPWD” command, leading to stack-based buffer overflows. This may result in Denial-of-Service conditions and Remote Code Execution. (FSMD-2021-0016)","cvss_v4":null,"cvss_v3":{"version":"3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","score":8.8},"cwes":["CWE-170","CWE-787"],"references":["https://cert-portal.siemens.com/productcert/pdf/ssa-044112.pdf","https://cert-portal.siemens.com/productcert/pdf/ssa-114589.pdf","https://cert-portal.siemens.com/productcert/pdf/ssa-044112.pdf","https://cert-portal.siemens.com/productcert/pdf/ssa-114589.pdf"],"products":["siemens:apogee_modular_building_controller_firmware","siemens:apogee_modular_equiment_controller_firmware","siemens:apogee_pxc_compact_firmware","siemens:apogee_pxc_modular_firmware","siemens:desigo_pxc00-e.d_firmware","siemens:desigo_pxc00-u_firmware","siemens:desigo_pxc001-e.d_firmware","siemens:desigo_pxc100-e.d_firmware","siemens:desigo_pxc12-e.d_firmware","siemens:desigo_pxc128-u_firmware","siemens:desigo_pxc200-e.d_firmware","siemens:desigo_pxc22-e.d_firmware","siemens:desigo_pxc22.1-e.d_firmware","siemens:desigo_pxc36.1-e.d_firmware","siemens:desigo_pxc50-e.d_firmware","siemens:desigo_pxc64-u_firmware","siemens:desigo_pxm20-e_firmware","siemens:nucleus_net","siemens:nucleus_readystart_v3","siemens:nucleus_source_code","siemens:talon_tc_compact_firmware","siemens:talon_tc_modular_firmware"],"source":"nvd","synced_at":"2026-10-19T21:24:39.218183596+00:00"},"epss":{"cve":"CVE-2021-31887","score":0.02449,"percentile":0.84372,"date":"2026-10-31"},"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."]}