CVE-2021-1385: Cisco IOS

Medium severity, CVSS 6.5. EPSS: 2.7% chance of exploitation in the next 30 days.

A vulnerability in the Cisco IOx application hosting environment of multiple Cisco platforms could allow an authenticated, remote attacker to conduct directory traversal attacks and read and write files on the underlying operating system or host system. This vulnerability occurs because the device does not properly validate URIs in IOx API requests. An attacker could exploit this vulnerability by sending a crafted API request that contains directory traversal character sequences to an affected device. A successful exploit could allow the attacker to read or write arbitrary files on the underlying operating system.

Affected products

• Cisco IOS: version 15.8(3)m2a only; version 15.8(3)m3 only; version 15.8(3)m4 only; version 15.8(3)m5 only; version 15.8(3)m6 only; version 15.9(3)m only; …
• Cisco IOS XE: version 16.11.1 only; version 16.11.1a only; version 16.11.1b only; version 16.11.1c only; version 16.11.1s only; version 16.11.2 only; …

Published 2021-03-24. Last modified 2026-06-17.