A vulnerability in the Distance Vector Multicast Routing Protocol (DVMRP) of Juniper Networks Junos OS on the QFX10K Series switches allows an attacker to trigger a packet forwarding loop, leading to a partial Denial of Service (DoS). The issue is caused by DVMRP packets looping on a multi-homed Ethernet Segment Identifier (ESI) when VXLAN is configured. DVMRP packets received on a multi-homed ESI are sent to the peer, and then incorrectly forwarded out the same ESI, violating the split horizon rule. This issue only affects QFX10K Series switches, including the QFX10002, QFX10008, and QFX10016. Other products and platforms are unaffected by this vulnerability. This issue affects Juniper Networks Junos OS on QFX10K Series: 17.3 versions prior to 17.3R3-S12; 17.4 versions prior to 17.4R3-S5;
The following software releases have been updated to resolve this specific issue: Junos OS 17.3R3-S12, 17.4R3-S5, 18.1R3-S13, 18.3R3-S5, 18.4R2-S9, 18.4R3-S8, 19.1R3-S5, 19.2R1-S7, 19.2R3-S2, 19.3R3-S2, 19.4R3-S3, 20.1R2-S2, 20.1R3, 20.2R3, 20.3R3, 20.4R2, 21.1R1, and all subsequent releases.
There are no viable workarounds for this issue. Service may be temporarily restored by disabling/enabled the IRB affected by this issue. Note that this will cause a temporary service interruption as the interface is flapped.
| Product | Vulnerable range | Fixed version | Advisory |
|---|---|---|---|
| Juniper Networks Junos OS | >=17.3<17.3R3-S12 | 17.3R3-S12 | advisory ↗ |
| Juniper Networks Junos OS | >=17.4<17.4R3-S5 | 17.4R3-S5 | advisory ↗ |
| Juniper Networks Junos OS | >=18.1<18.1R3-S13 | 18.1R3-S13 | advisory ↗ |
| Juniper Networks Junos OS | >=18.2R1<18.2* | 18.2* | advisory ↗ |
| Juniper Networks Junos OS | >=18.3<18.3R3-S5 | 18.3R3-S5 | advisory ↗ |
| Juniper Networks Junos OS | >=18.4<18.4R2-S9, 18.4R3-S8 | 18.4R2-S9, 18.4R3-S8 | advisory ↗ |
| Juniper Networks Junos OS | >=19.1<19.1R3-S5 | 19.1R3-S5 | advisory ↗ |
| Juniper Networks Junos OS | >=19.2<19.2R1-S7, 19.2R3-S2 | 19.2R1-S7, 19.2R3-S2 | advisory ↗ |
| Juniper Networks Junos OS | >=19.3<19.3R3-S2 | 19.3R3-S2 | advisory ↗ |
| Juniper Networks Junos OS | >=19.4<19.4R3-S3 | 19.4R3-S3 | advisory ↗ |
| Juniper Networks Junos OS | >=20.1<20.1R2-S2, 20.1R3 | 20.1R2-S2, 20.1R3 | advisory ↗ |
| Juniper Networks Junos OS | >=20.2<20.2R3 | 20.2R3 | advisory ↗ |
| Juniper Networks Junos OS | >=20.3<20.3R3 | 20.3R3 | advisory ↗ |
| Juniper Networks Junos OS | >=20.4<20.4R2 | 20.4R2 | advisory ↗ |