CVE-2021-1389

6.5 mediumEPSS 1.2%

Medium (6.5) in cisco. EPSS 1.2% chance of exploitation in the next 30 days.

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.

Severity

CVSS 3.1

6.5 medium

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N

EPSS: 1.2% chance of exploitation in the next 30 days; higher than 69% of CVEs (scores of 2026-10-31)
CWE: CWE-284
Published: 2021-02-04
Modified: 2026-06-17
Record from: the NVD, synced 2026-10-19

Affected

cisco:ios_xr
cisco:nx-os

References

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