CVE-2021-21005
Race Condition Vulnerability in Phoenix Contact FL SWITCH SMCS series products
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.
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
- High
Exploit likelihood
What each source reports
CVE List Score used
Race Condition Vulnerability in Phoenix Contact FL SWITCH SMCS series products
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.
- Record
CVE-2021-21005- CVSS 3.1
- 7.5 High
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H - Weakness
- CWE-362
- Updated
- 2026-11-02
EUVDEUVD-2021-8414
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.
- Record
EUVD-2021-8414- CVSS 3.1
- 7.5 High
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H - Updated
- 2026-11-03
GitHub AdvisoriesGHSA-jmcx-w32h-8qj4 No score
In Phoenix Contact FL SWITCH SMCS series products in multiple versions if an attacker sends a...
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.
- Record
GHSA-jmcx-w32h-8qj4- Weakness
- CWE-362
- Updated
- 2026-11-02
NVD
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.
- Record
CVE-2021-21005- CVSS 3.1
- 7.5 High
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H - CVSS 2.0
- 7.8 High
AV:N/AC:L/Au:N/C:N/I:N/A:C - Weakness
- CWE-362
- 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-2021-21005 is a high vulnerability (CVSS 7.5) 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 0.68%, the 52nd percentile. No source names a fixed version.