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CVE-2022-20821

KEVCisco IOS XR Open Port Vulnerability

Cisco IOS XR software health check opens TCP port 6379 by default on activation. An attacker can connect to the Redis instance on the open port and allow access to the Redis instance that is running within the NOSi container.

A vulnerability in the health check RPM of Cisco IOS XR Software could allow an unauthenticated, remote attacker to access the Redis instance that is running within the NOSi container. This vulnerability exists because the health check RPM opens TCP port 6379 by default upon activation. An attacker could exploit this vulnerability by connecting to the Redis instance on the open port. A successful exploit could allow the attacker to write to the Redis in-memory database, write arbitrary files to the container filesystem, and retrieve information about the Redis database. Given the configuration of the sandboxed container that the Redis instance runs in, a remote attacker would be unable to execute remote code or abuse the integrity of the Cisco IOS XR Software host system.

CVSS 3.1 vectorCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N
PublishedMay 26, 2022
Last modifiedJun 17, 2026
Added to KEVMay 23, 2022
Remediation dueJun 13, 2022
    64
    Risk assessment · High

    Actively exploited. Patch immediately.

    Exploitation
    Confirmed in the wild (CISA KEV)
    Federal remediation deadline
    Overdue by 1597 days
    CVSS
    6.5 MEDIUM
    EPSS (30-day exploit probability)
    11.5% · top 4% of all CVEs
    Weakness
    CWE-200
    Attack vector
    Network, remotely reachable
    Preconditions
    No privileges and no user interaction
    1. 1.Apply updates per vendor instructions.
    2. 2.Treat as emergency change: patch or isolate internet-facing instances first.
    3. 3.Review exposure: confirm which instances are reachable from the internet and restrict access until patched.
    4. 4.Hunt for compromise: review logs for the disclosure window, not just from the patch date.

    Assessment is derived automatically from the live signals above; verify against your own asset inventory.