CVE-2021-21003
Denial of Service Vulnerability in Phoenix Contact FL SWITCH SMCS series products
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.
Attack profile
How easy it is to exploit
- Attack vector
- Network
- Complexity
- Low
- Privileges needed
- None
- User interaction
- None
What an attacker can affect
- Confidentiality
- None
- Integrity
- None
- Availability
- Low
Exploit likelihood
What each source reports
CVE List Score used
Denial of Service Vulnerability in Phoenix Contact FL SWITCH SMCS series products
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.
- Record
CVE-2021-21003- CVSS 3.1
- 5.3 Medium
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L - Weakness
- CWE-404
- Updated
- 2026-11-02
EUVDEUVD-2021-8412
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.
- Record
EUVD-2021-8412- CVSS 3.1
- 5.3 Medium
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L - Updated
- 2026-11-03
GitHub AdvisoriesGHSA-4567-7fw8-972r No score
In Phoenix Contact FL SWITCH SMCS series products in multiple versions fragmented TCP-Packets may...
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.
- Record
GHSA-4567-7fw8-972r- Weakness
- CWE-404
- Updated
- 2026-11-02
NVD
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.
- Record
CVE-2021-21003- CVSS 3.1
- 5.3 Medium
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L - CVSS 2.0
- 5.0 Medium
AV:N/AC:L/Au:N/C:N/I:N/A:P - Weakness
- CWE-404
- Updated
- 2026-11-02
Affected products
- phoenix contact fl switch
- phoenix contact fl nat
- 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
History
| Recorded | Changed | Sources |
|---|---|---|
| facts | ||
| aliases, published | EUVD | |
| first indexed | CVE List, GitHub Advisories, NVD |
Dates are when Every CVE recorded each change. Upstream dates may differ.
In short
CVE-2021-21003 is a medium vulnerability (CVSS 5.3) in Phoenix Contact Fl Switch, published June 25, 2021. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 0.95%, the 61st percentile. No source names a fixed version.