If eero Pro 5 devices receive an IPv6 packet where the payload length is zero and contains a hop-by-hop or destination options extension header that refers to another hop-by-hop or destination options extension header that doesn't exist (because the packet ends before providing the content for it) then the Ethernet interface will stop receiving any further packets. Transmission over Ethernet, and all WiFi communication is unaffected.
All testing has been performed with a network of multiple eeros in "bridge" mode. If a broadcast packet is used then all devices are affected at the same time and there will be a complete loss of inbound Ethernet communication for about 8 minutes until they automatically recover.
If a single eero is targeted then it will fallback to communicating with other eeros over WiFi and start bridging all the traffic it receives out the Ethernet interface (which is now transmit-only) with the corresponding problems that occur with a bridged network loop. As long as it can still communicate with other eeros it doesn't appear to automatically recover from this.
In both cases the effect is not permanent and the device can be rebooted to recover immediately.
The packet can be unicast or multicast and does not need to be directed at the eero's MAC or IPv6 address. In theory, if a unicast packet with these characteristics could be routed over the Internet to an IPv6 host on the WiFi network then it could be used to target eero devices remotely. In practise it does not appear to be possible to get such a packet through a bridge/router because it is malformed.
CVSS: 6.5 (AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H/E:H/RL:U/RC:C)
Versions affected:
- eeroOS v6.9.0 and later
- 2022-08-05: Reported issue with eeroOS v6.9.0 and v6.10.3 on eero Pro 5 to eero
- 2022-08-06: Issue acknowledged
- 2022-10-09: Requested a timeline for when this will be fixed (no response)
- 2022-12-12: Received claim that it has been fixed in eeroOS v6.13
- 2022-12-12: Reported that issue remains with eeroOS v6.13.3-11 (no response)
- 2023-09-30: Confirmed issue is still present in v6.15.2-99
- 2023-09-30: Confirmed issue is still present in v6.16.4-11
- 2023-09-30: Public release