CVE-2021-21005: phoenix contact fl nat Race Condition
CVSS: 7.8v2.0HighModified
Published 25-06-2021Last modified 17-09-2024
Vulnerability summary
CVE-2021-21005 is a high (CVSS 7.8) Race Condition vulnerability in phoenix contact fl nat. EPSS estimates a 0.68% chance of exploitation in the next 30 days, higher than 51.3% of scored vulnerabilities.
CVSS score
7.8/10
010
High · v2.0 (NVD)EPSS score
0.68%
0%100%
Low · 0.00 pp in 30 daysKEVNot listedIn no KEV catalog
RansomwareNone recordedNo known use recorded
Public exploits0No public exploits recorded
Timeline
- 25-06-2021PublishedVulnerability first disclosed.
- 17-09-2024Last modifiedVulnerability information updated.
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.
CVSS metrics
3 scores · 2 sources · 2 versionsHigh 7.5Preferred score · CVE.org (CNA)
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:HSourcesAll 2 agree
- NVDNIST7.5HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
High 7.8Preferred score · NVD (NIST)
AV:N/AC:L/Au:N/C:N/I:N/A:CSourcesSingle source
EPSS trend
Probability
0.68%
Chance of exploitation in the next 30 days
Percentile
51%
Versus all other CVEs
30-day change
0.00 pp
From 0.68% on 18-09-2026
18-09-202618-10-2026
EPSS score0.68%
Known exploited
Compare KEV catalogsNot in any of the 3 tracked catalogs.
Public exploits
0 foundNo public exploits indexed.
Weaknesses
CWE · root causeAffected systems
Phoenixcontact15 products
- fl_nat_smn_8tx_firmware≤ 4.63
- fl_nat_smn_8tx-m_firmware≤ 4.63
- fl_switch_smcs_14tx\/2fx_firmware≤ 4.70
- fl_switch_smcs_14tx\/2fx-sm_firmware≤ 4.70
- fl_switch_smcs_16tx_firmware≤ 4.70
Phoenix contact2 products
- fl nat≥ SMN 8TX (2989365), ≤ 4.63 | ≥ SMN 8TX-M (2702443), ≤ 4.63
- fl switch≥ SMCS 16TX (2700996), ≤ 4.70 | ≥ SMCS 14TX/2FX (2700997), ≤ 4.70 | ≥ SMCS 14TX/2FX-SM (2701466), ≤ 4.70 | ≥ SMCS 8GT (2891123), ≤ 4.70 | ≥ SMCS 6GT/2SFP (2891479), ≤ 4.70 | ≥ SMCS 8TX-PN (2989103), ≤ 4.70 | ≥ SMCS 4TX-PN (2989093), ≤ 4.70 | ≥ SMCS 8TX (2989226), ≤ 4.70 | ≥ SMCS 6TX/2SFP (2989323), ≤ 4.70 | ≥ SMN 6TX/2POF-PN (2700290), ≤ 4.70 | ≥ SMN 8TX-PN (2989501), ≤ 4.70 | ≥ SMN 6TX/2FX (2989543), ≤ 4.70 | ≥ SMN 6TX/2FX SM (2989556), ≤ 4.70
2 vendors · 17 products