CVE-2021-1423: Cisco Aironet Access Points Arbitrary File Overwrite Vulnerability

Severity: medium (CVSS 4.4 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.2% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2021-03-24 · updated 2026-06-17
Weakness: CWE-668

Description

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.

Affected products

Cisco Mobility Express 1800 Access Point Series: all versions
Cisco Catalyst 9800 Firmware: before 16.12.5; from 17.1 through 17.2 — fixed in 16.12.5
Cisco Wireless LAN Controller (WLC): before 8.5.171.0; from 8.6 before 8.10.130.0 — fixed in 8.10.130.0, 8.5.171.0

How to fix

Upgrade to a fixed version: Cisco Catalyst 9800 Firmware 16.12.5; Cisco Wireless LAN Controller (WLC) 8.10.130.0, 8.5.171.0. Check the vendor advisory for mitigations.

References

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