CVE-2021-21005
7.5 · HIGHOverview
CVE-2021-21005 is a high-severity vulnerability affecting phoenixcontact fl_switch_smcs_16tx_firmware. It was published on June 25, 2021 and has a CVSS 3.1 base score of 7.5 (HIGH).
This vulnerability has a CVSS 3.1 base score of 7.5, rated HIGH. It can be exploited remotely over the network. No authentication or special privileges are required for exploitation.
Technical Description
In Phoenix Contact FL SWITCH SMCS series products in multiple versions if an attacker sends a hand-crafted TCP-Packet with the Urgent-Flag set and the Urgent-Pointer set to 0, the network stack will crash. The device needs to be rebooted afterwards.
Remediation
Check the references section for vendor advisories and patches from phoenixcontact. Update fl_switch_smcs_16tx_firmware to the latest patched version. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.
Affected Products
| Vendor | Product | Versions | Status |
|---|---|---|---|
| phoenixcontact | fl_switch_smcs_16tx_firmware | 0 | Affected |
| phoenixcontact | fl_switch_smcs_14tx\/2fx_firmware | 0 | Affected |
| phoenixcontact | fl_switch_smcs_14tx\/2fx-sm_firmware | 0 | Affected |
| phoenixcontact | fl_switch_smcs_8gt_firmware | 0 | Affected |
| phoenixcontact | fl_switch_smcs_6gt\/2sfp_firmware | 0 | Affected |
| phoenixcontact | fl_switch_smcs_8tx-pn_firmware | 0 | Affected |
| phoenixcontact | fl_switch_smcs_4tx-pn_firmware | 0 | Affected |
| phoenixcontact | fl_switch_smcs_8tx_firmware | 0 | Affected |
| phoenixcontact | fl_switch_smcs_6tx\/2sfp_firmware | 0 | Affected |
| phoenixcontact | fl_switch_smn_6tx\/2pof-pn_firmware | 0 | Affected |
Frequently Asked Questions
What is CVE-2021-21005?
CVE-2021-21005 is a high-severity vulnerability affecting phoenixcontact fl_switch_smcs_16tx_firmware. It was published on June 25, 2021 and has a CVSS 3.1 base score of 7.5 (HIGH).
How severe is CVE-2021-21005?
This vulnerability has a CVSS 3.1 base score of 7.5, rated HIGH. It can be exploited remotely over the network. No authentication or special privileges are required for exploitation.
How do I fix or remediate CVE-2021-21005?
Check the references section for vendor advisories and patches from phoenixcontact. Update fl_switch_smcs_16tx_firmware to the latest patched version. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.
How can CyberStrike help with CVE-2021-21005?
CyberStrike's AI-powered security agents can automatically detect CVE-2021-21005 across your infrastructure using autonomous pentesting, DAST scanning, and HackBrowser. The platform continuously monitors for known vulnerabilities and provides actionable remediation guidance prioritized by real-world exploitability.
How CyberStrike Helps
AI agents map your attack surface to find vulnerabilities like this one.
Automated penetration testing that runs continuously, not just quarterly.
AI-driven PR review catches vulnerable dependencies before they ship.
Browser-based exploitation validates findings with real proof-of-concept.
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