Improper access control in Cisco IOS XR and Cisco Nexus 9000 Series Switches - CVE-2021-1389
Published: February 4, 2021 / Updated: February 5, 2021
Vulnerability identifier: #VU50381
CSH Severity: Medium
CVSS v4: 6.9 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N]
CVE-ID: CVE-2021-1389
CWE-ID: CWE-284
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vulnerability details
The vulnerability allows a remote attacker to gain unauthorized access to otherwise restricted functionality.
The vulnerability exists due to improper access restrictions when processing IPv6 traffic in Cisco IOS XR Software and Cisco NX-OS Software for certain Cisco devices. A remote attacker can bypass implemented ACLs with specially crafted IPv6 packets.
this vulnerability affected the following Cisco devices if they were running a vulnerable release of Cisco IOS XR Software or Cisco NX-OS Software and had IPv6 ACL configured:
- Network Convergence System (NCS) 540 Series Routers
- NCS 560 Series Routers
- NCS 5500 Series
- Nexus 3600 Platform Switches
- Nexus 9500 R-Series Switching Platforms
Affected software
Cisco IOS XR
Cisco Nexus 9000 Series Switches
Cisco Nexus 9000 Series Switches
How to mitigate CVE-2021-1389
Install updates from vendor's website.
Cisco IOS XR - update to 7.2.0
Cisco Nexus 9000 Series Switches - addressed in versions 9.3.5.80, 9.3.5.106, 9.3.5.115, 9.3.5.127, 9.3.6, 10.1.0.324, 10.1.1
Cisco Nexus 9000 Series Switches - addressed in versions 9.3.5.80, 9.3.5.106, 9.3.5.115, 9.3.5.127, 9.3.6, 10.1.0.324, 10.1.1