What is CVE-2021-1423?

CVE-2021-1423 is a medium-severity vulnerability in Cisco 1100 Integrated Services Router, classified under Exposure of Resource to Wrong Sphere. CVSS score: 4.4/10. Published 2021-03-24.

How severe is CVE-2021-1423?

Medium severity. CVSS v3 base score is 4.4 out of 10.

Vulnerability in Cisco 1100 Integrated Services Router

CVE-2021-1423

A vulnerability in the implementation of a CLI command in Cisco Aironet Access Points (AP) could allow an authenticated, local attacker to overwrite files in the flash memory of the device. This vulnerability is due to insufficient input validation for a specific command. An attacker could exploit this vulnerability by issuing a command with crafted arguments. A successful exploit could allow the attacker to overwrite or create files with data that is already present in other files that are hosted on the affected device.

Published 2021-03-24 · last modified 2026-06-17.

CVSS v3 metric

CVSS v3 base score 4.4 (Medium). Vector: CVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:U/C:N/I:H/A:N.

EPSS exploit prediction

EPSS: 0.002 (14.9th percentile), scored 2026-11-02.

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 15th percentile — 14.9% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.002 · newest: 0.002 · change: +0.000

Affected products

Weakness classification (CWE)

CWE-668 — Exposure of Resource to Wrong Sphere

References

tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-ap-fover… (vendor-advisory, Vendor Advisory)

Frequently asked questions

What is CVE-2021-1423?: CVE-2021-1423 is a medium-severity vulnerability in Cisco 1100 Integrated Services Router, classified under Exposure of Resource to Wrong Sphere. CVSS score: 4.4/10. Published 2021-03-24.
How severe is CVE-2021-1423?: Medium severity. CVSS v3 base score is 4.4 out of 10.