SB2021020507 - IPV6 ACL bypass in Cisco IOS XR and Cisco NX-OS Software

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Main Vulnerability Database SB2021020507

SB2021020507 - IPV6 ACL bypass in Cisco IOS XR and Cisco NX-OS Software

Published: February 5, 2021

Security Bulletin ID SB2021020507
CSH Severity
Medium
Patch available
YES
Number of vulnerabilities 1
Exploitation vector Remote access
Highest impact Data manipulation

Breakdown by Severity

Medium 100%
  • Low
  • Medium
  • High
  • Critical

Description

This security bulletin contains information about 1 vulnerability.


1) Improper access control (CVE-ID: CVE-2021-1389)

CWE-ID: CWE-284 - Improper Access Control

CVSSv4: 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/E:U/U:Green


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

Remediation

Install update from vendor's website.

References