CVE-2022-20821: in the CISA KEV catalogue
Cisco IOS XR Open Port Vulnerability. CISA added CVE-2022-20821 to the Known Exploited Vulnerabilities catalogue on 2022-05-23 with a default due date of 2022-06-13. Known ransomware campaign use: Unknown. Forensic triage flag: No.
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. (CISA description)
- Vendor / product
- Cisco IOS XR
- CWE
- CWE-923
- CISA required action
- Apply updates per vendor instructions.
- EPSS
- 11%, percentile 96 (scored 2026-11-03)
EPSS puts about 11 in 100 odds (11%) on exploitation activity being observed in the next 30 days. Its score is higher than or equal to that of 96% of scored CVEs. This is a model estimate about exploitation anywhere, not about your environment.
Vendor and reference links (from CISA)
Your own deadline under CISA BOD 26-04 depends on exposure, automatability and technical impact: work it out with the BOD 26-04 calculator.
Frequently asked questions
Is CVE-2022-20821 in the CISA KEV catalogue?
Yes. CISA added CVE-2022-20821 (Cisco IOS XR Open Port Vulnerability) to the Known Exploited Vulnerabilities catalogue on 2022-05-23. CISA's default due date for it is 2022-06-13.
Is CVE-2022-20821 used in ransomware attacks?
CISA marks known ransomware campaign use as Unknown for CVE-2022-20821. That means CISA lacks confirmation, not that ransomware groups do not use it.
What should I do about CVE-2022-20821?
CISA's required action: Apply updates per vendor instructions.
Sources
- CISA, Known Exploited Vulnerabilities Catalog (accessed 2026-11-03)
- FIRST, Exploit Prediction Scoring System (EPSS) (EPSS by FIRST; scores generated by Empirical Security)
- NVD record for CVE-2022-20821