CVE-2021-0228
Junos OS: MX Series: DDoS LACP violation upon receipt of specific layer 2 frames in EVPN-VXLAN deployment
An improper check for unusual or exceptional conditions vulnerability in Juniper Networks MX Series platforms with Trio-based MPC (Modular Port Concentrator) deployed in (Ethernet VPN) EVPN-(Virtual Extensible LAN) VXLAN configuration, may allow an attacker sending specific Layer 2 traffic to cause Distributed Denial of Service (DDoS) protection to trigger unexpectedly, resulting in traffic impact. Continued receipt and processing of this specific Layer 2 frames will sustain the Denial of Service (DoS) condition. An indication of compromise is to check DDOS LACP violations: user@device> show ddos-protection protocols statistics brief | match lacp This issue only affects the MX Series platforms with Trio-based MPC. No other products or platforms are affected. This issue affects: Juniper Networks Junos OS on MX Series: 15.1 versions prior to 15.1R7-S9; 17.3 versions prior to 17.3R3-S11; 17.4 versions prior to 17.4R3-S4; 18.1 versions prior to 18.1R3-S12; 18.2 versions prior to 18.2R2-S8, 18.2R3-S8; 18.3 versions prior to 18.3R3-S4; 18.4 versions prior to 18.4R1-S8, 18.4R2-S7, 18.4R3-S7; 19.1 versions prior to 19.1R3-S4; 19.2 versions prior to 19.2R1-S6; 19.3 versions prior to 19.3R3-S2; 19.4 versions prior to 19.4R2-S4, 19.4R3-S2; 20.1 versions prior to 20.1R2, 20.1R3; 20.2 versions prior to 20.2R2-S1, 20.2R3; 20.3 versions prior to 20.3R1-S1, 20.3R2;
Attack profile
How easy it is to exploit
- Attack vector
- Adjacent 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
6.5
Junos OS: MX Series: DDoS LACP violation upon receipt of specific layer 2 frames in EVPN-VXLAN deployment
An improper check for unusual or exceptional conditions vulnerability in Juniper Networks MX Series platforms with Trio-based MPC (Modular Port Concentrator) deployed in (Ethernet VPN) EVPN-(Virtual Extensible LAN) VXLAN configuration, may allow an attacker sending specific Layer 2 traffic to cause Distributed Denial of Service (DDoS) protection to trigger unexpectedly, resulting in traffic impact. Continued receipt and processing of this specific Layer 2 frames will sustain the Denial of Service (DoS) condition. An indication of compromise is to check DDOS LACP violations: user@device> show ddos-protection protocols statistics brief | match lacp This issue only affects the MX Series platforms with Trio-based MPC. No other products or platforms are affected. This issue affects: Juniper Networks Junos OS on MX Series: 15.1 versions prior to 15.1R7-S9; 17.3 versions prior to 17.3R3-S11; 17.4 versions prior to 17.4R3-S4; 18.1 versions prior to 18.1R3-S12; 18.2 versions prior to 18.2R2-S8, 18.2R3-S8; 18.3 versions prior to 18.3R3-S4; 18.4 versions prior to 18.4R1-S8, 18.4R2-S7, 18.4R3-S7; 19.1 versions prior to 19.1R3-S4; 19.2 versions prior to 19.2R1-S6; 19.3 versions prior to 19.3R3-S2; 19.4 versions prior to 19.4R2-S4, 19.4R3-S2; 20.1 versions prior to 20.1R2, 20.1R3; 20.2 versions prior to 20.2R2-S1, 20.2R3; 20.3 versions prior to 20.3R1-S1, 20.3R2;
- Record
CVE-2021-0228- CVSS 3.1
- 6.5 Medium
CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H - Weakness
- CWE-754
- Updated
- 2026-11-02
EUVDEUVD-2021-2847
6.5
An improper check for unusual or exceptional conditions vulnerability in Juniper Networks MX Series platforms with Trio-based MPC (Modular Port Concentrator) deployed in (Ethernet VPN) EVPN-(Virtual Extensible LAN) VXLAN configuration, may allow an attacker sending specific Layer 2 traffic to cause Distributed Denial of Service (DDoS) protection to trigger unexpectedly, resulting in traffic impact. Continued receipt and processing of this specific Layer 2 frames will sustain the Denial of Service (DoS) condition. An indication of compromise is to check DDOS LACP violations: user@device> show ddos-protection protocols statistics brief | match lacp This issue only affects the MX Series platforms with Trio-based MPC. No other products or platforms are affected. This issue affects: Juniper Networks Junos OS on MX Series: 15.1 versions prior to 15.1R7-S9; 17.3 versions prior to 17.3R3-S11; 17.4 versions prior to 17.4R3-S4; 18.1 versions prior to 18.1R3-S12; 18.2 versions prior to 18.2R2-S8, 18.2R3-S8; 18.3 versions prior to 18.3R3-S4; 18.4 versions prior to 18.4R1-S8, 18.4R2-S7, 18.4R3-S7; 19.1 versions prior to 19.1R3-S4; 19.2 versions prior to 19.2R1-S6; 19.3 versions prior to 19.3R3-S2; 19.4 versions prior to 19.4R2-S4, 19.4R3-S2; 20.1 versions prior to 20.1R2, 20.1R3; 20.2 versions prior to 20.2R2-S1, 20.2R3; 20.3 versions prior to 20.3R1-S1, 20.3R2;
- Record
EUVD-2021-2847- CVSS 3.1
- 6.5 Medium
CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H - Updated
- 2026-11-03
GitHub AdvisoriesGHSA-389v-3v24-gh3w No score
An improper check for unusual or exceptional conditions vulnerability in Juniper Networks MX...
An improper check for unusual or exceptional conditions vulnerability in Juniper Networks MX Series platforms with Trio-based MPC (Modular Port Concentrator) deployed in (Ethernet VPN) EVPN-(Virtual Extensible LAN) VXLAN configuration, may allow an attacker sending specific Layer 2 traffic to cause Distributed Denial of Service (DDoS) protection to trigger unexpectedly, resulting in traffic impact. Continued receipt and processing of this specific Layer 2 frames will sustain the Denial of Service (DoS) condition. An indication of compromise is to check DDOS LACP violations: user@device> show ddos-protection protocols statistics brief | match lacp This issue only affects the MX Series platforms with Trio-based MPC. No other products or platforms are affected. This issue affects: Juniper Networks Junos OS on MX Series: 15.1 versions prior to 15.1R7-S9; 17.3 versions prior to 17.3R3-S11; 17.4 versions prior to 17.4R3-S4; 18.1 versions prior to 18.1R3-S12; 18.2 versions prior to 18.2R2-S8, 18.2R3-S8; 18.3 versions prior to 18.3R3-S4; 18.4 versions prior to 18.4R1-S8, 18.4R2-S7, 18.4R3-S7; 19.1 versions prior to 19.1R3-S4; 19.2 versions prior to 19.2R1-S6; 19.3 versions prior to 19.3R3-S2; 19.4 versions prior to 19.4R2-S4, 19.4R3-S2; 20.1 versions prior to 20.1R2, 20.1R3; 20.2 versions prior to 20.2R2-S1, 20.2R3; 20.3 versions prior to 20.3R1-S1, 20.3R2;
- Record
GHSA-389v-3v24-gh3w- Weakness
- CWE-754
- Updated
- 2026-11-02
NVD
6.5
An improper check for unusual or exceptional conditions vulnerability in Juniper Networks MX Series platforms with Trio-based MPC (Modular Port Concentrator) deployed in (Ethernet VPN) EVPN-(Virtual Extensible LAN) VXLAN configuration, may allow an attacker sending specific Layer 2 traffic to cause Distributed Denial of Service (DDoS) protection to trigger unexpectedly, resulting in traffic impact. Continued receipt and processing of this specific Layer 2 frames will sustain the Denial of Service (DoS) condition. An indication of compromise is to check DDOS LACP violations: user@device> show ddos-protection protocols statistics brief | match lacp This issue only affects the MX Series platforms with Trio-based MPC. No other products or platforms are affected. This issue affects: Juniper Networks Junos OS on MX Series: 15.1 versions prior to 15.1R7-S9; 17.3 versions prior to 17.3R3-S11; 17.4 versions prior to 17.4R3-S4; 18.1 versions prior to 18.1R3-S12; 18.2 versions prior to 18.2R2-S8, 18.2R3-S8; 18.3 versions prior to 18.3R3-S4; 18.4 versions prior to 18.4R1-S8, 18.4R2-S7, 18.4R3-S7; 19.1 versions prior to 19.1R3-S4; 19.2 versions prior to 19.2R1-S6; 19.3 versions prior to 19.3R3-S2; 19.4 versions prior to 19.4R2-S4, 19.4R3-S2; 20.1 versions prior to 20.1R2, 20.1R3; 20.2 versions prior to 20.2R2-S1, 20.2R3; 20.3 versions prior to 20.3R1-S1, 20.3R2;
- Record
CVE-2021-0228- CVSS 3.1
- 6.5 Medium
CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H - CVSS 2.0
- 3.3 Low
AV:A/AC:L/Au:N/C:N/I:N/A:P - Weakness
- CWE-754
- Updated
- 2026-11-02
Affected products
History
| Recorded | Changed | Sources |
|---|---|---|
| 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-2021-0228 is a medium vulnerability (CVSS 6.5) in Juniper Junos, published April 22, 2021. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 0.40%, the 34th percentile. No source names a fixed version.