CVE-2021-1389: medium-severity vulnerability in Cisco IOS XR Software
Cisco IOS XR and Cisco NX-OS Software IPv6 Access Control List Bypass Vulnerability
Published · Updated
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13Vexday Risk Score
No sign of exploitation. No public exploitation artifact known so far.
ssvc Trackcvss 5.8epss 1.2%
A vulnerability in the IPv6 traffic processing of Cisco IOS XR Software and Cisco NX-OS Software for certain Cisco devices could allow an unauthenticated, remote attacker to bypass an IPv6 access control list (ACL) that is configured for an interface of an affected device. The vulnerability is due to improper processing of IPv6 traffic that is sent through an affected device. An attacker could exploit this vulnerability by sending crafted IPv6 packets that traverse the affected device. A successful exploit could allow the attacker to access resources that would typically be protected by the interface ACL.
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:L/A:N
Affected products
Cisco · Cisco IOS XR SoftwareRelated CVEs — Cisco IOS XR Software
In the same product, most dangerous first.
CVE-2020-3118HIGHCisco IOS XR Software Cisco Discovery Protocol Format String VulnerabilityEPSS 11.7%KEVCVE-2022-20821MEDIUMCisco IOS XR Software Health Check Open Port VulnerabilityEPSS 11.5%KEVCVE-2020-3566HIGHCisco IOS XR Software DVMRP Memory Exhaustion VulnerabilityEPSS 3.7%KEVCVE-2020-3569HIGHCisco IOS XR Software DVMRP Memory Exhaustion VulnerabilitiesEPSS 3.3%KEVCVE-2025-20363CRITICALCVE-2025-20363EPSS 7.2%CVE-2020-3284HIGHCisco IOS XR Software Enhanced Preboot eXecution Environment Unsigned Code Execution VulnerabilityEPSS 2.9%