{"cve":"CVE-2021-21003","nvd":{"published":"2021-06-25T19:15:08.660","modified":"2026-06-17T03:34:38.447","status":"Modified","description":"In Phoenix Contact FL SWITCH SMCS series products in multiple versions fragmented TCP-Packets may cause a Denial of Service of Web-, SNMP- and ICMP-Echo services. The switching functionality of the device is not affected.","cvss_v4":null,"cvss_v3":{"version":"3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L","score":5.3},"cwes":["CWE-404"],"references":["https://cert.vde.com/en-us/advisories/vde-2021-023","https://cert.vde.com/en-us/advisories/vde-2021-023"],"products":["phoenixcontact:fl_nat_smn_8tx-m_firmware","phoenixcontact:fl_nat_smn_8tx_firmware","phoenixcontact:fl_switch_smcs_14tx\\/2fx-sm_firmware","phoenixcontact:fl_switch_smcs_14tx\\/2fx_firmware","phoenixcontact:fl_switch_smcs_16tx_firmware","phoenixcontact:fl_switch_smcs_4tx-pn_firmware","phoenixcontact:fl_switch_smcs_6gt\\/2sfp_firmware","phoenixcontact:fl_switch_smcs_6tx\\/2sfp_firmware","phoenixcontact:fl_switch_smcs_8gt_firmware","phoenixcontact:fl_switch_smcs_8tx-pn_firmware","phoenixcontact:fl_switch_smcs_8tx_firmware","phoenixcontact:fl_switch_smn_6tx\\/2fx_firmware","phoenixcontact:fl_switch_smn_6tx\\/2fx_sm_firmware","phoenixcontact:fl_switch_smn_6tx\\/2pof-pn_firmware","phoenixcontact:fl_switch_smn_8tx-pn_firmware"],"source":"nvd","synced_at":"2026-10-19T21:20:07.141963181+00:00"},"epss":{"cve":"CVE-2021-21003","score":0.00946,"percentile":0.6111,"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."]}