High severity · published Apr 12, 2021
CVE-2021-3128
In ASUS RT-AX3000, ZenWiFi AX (XT8), RT-AX88U, and other ASUS routers with firmware < 3.0.0.4.386.42095 or < 9.0.0.4.386.41994, when IPv6 is used, a routing loop can occur that…
7.5
CVSS
2.2%
EPSS
No
On KEV
Description
In ASUS RT-AX3000, ZenWiFi AX (XT8), RT-AX88U, and other ASUS routers with firmware < 3.0.0.4.386.42095 or < 9.0.0.4.386.41994, when IPv6 is used, a routing loop can occur that generates excessive network traffic between an affected device and its upstream ISP's router. This occurs when a link prefix route points to a point-to-point link, a destination IPv6 address belongs to the prefix and is not a local IPv6 address, and a router advertisement is received with at least one global unique IPv6 prefix for which the on-link flag is set.
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
None
Confidentiality
None
Integrity
None
Availability
High
Scope
Unchanged
Exploitation
Is it being used?
Exploit prediction (EPSS)2.2% · higher than 82% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
RB
Rt-ac1750 B1 Firmware · Asus
before 3.0.0.4.386.42095; before 9.0.0.4.386.41994 · source: NVD
RF
Rt-ac1900 Firmware · Asus
before 3.0.0.4.386.42095; before 9.0.0.4.386.41994 · source: NVD
RF
Rt-ac1900p Firmware · Asus
before 3.0.0.4.386.42095; before 9.0.0.4.386.41994 · source: NVD
RF
Rt-ac1900u Firmware · Asus
before 3.0.0.4.386.42095; before 9.0.0.4.386.41994 · source: NVD
RF
Rt-ac2900 Firmware · Asus
before 3.0.0.4.386.42095; before 9.0.0.4.386.41994 · source: NVD
RF
Rt-ac3100 Firmware · Asus
before 3.0.0.4.386.42095; before 9.0.0.4.386.41994 · source: NVD
RF
Rt-ac5300 Firmware · Asus
before 3.0.0.4.386.42095; before 9.0.0.4.386.41994 · source: NVD
RF
Rt-ac58u Firmware · Asus
before 3.0.0.4.386.42095; before 9.0.0.4.386.41994 · source: NVD
RF
Rt-ac65u Firmware · Asus
before 3.0.0.4.386.42095; before 9.0.0.4.386.41994 · source: NVD
RB
Rt-ac66u B1 Firmware · Asus
before 3.0.0.4.386.42095; before 9.0.0.4.386.41994 · source: NVD
RF
Rt-ac68p Firmware · Asus
before 3.0.0.4.386.42095; before 9.0.0.4.386.41994 · source: NVD
RF
Rt-ac68r Firmware · Asus
before 3.0.0.4.386.42095; before 9.0.0.4.386.41994 · source: NVD
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2021-3128
CVE.org
https://www.cve.org/CVERecord?id=CVE-2021-3128
Product
https://www.asus.com/Networking-IoT-Servers/Whole-Home-Mesh-WiFi-System/ZenWiFi-WiFi-Systems/ASUS-ZenWiFi-AX-XT8-/HelpDesk_BIOS/
Product
https://www.asus.com/Networking-IoT-Servers/WiFi-6/All-series/RT-AX3000/HelpDesk_BIOS/
Product
https://www.asus.com/Networking-IoT-Servers/WiFi-6/All-series/RT-AX55/HelpDesk_BIOS/
Product
https://www.asus.com/Networking-IoT-Servers/WiFi-6/All-series/RT-AX56U/HelpDesk_BIOS/
Product
https://www.asus.com/Networking-IoT-Servers/WiFi-6/All-series/RT-AX58U/HelpDesk_BIOS/
Product
https://www.asus.com/Networking-IoT-Servers/WiFi-6/All-series/RT-AX68U/HelpDesk_BIOS/