CVE-2021-1435: Cisco IOS XE Software Web UI Command Injection Vulnerability

Published Mar 24, 2021
·
Updated

Cisco IOS XE contains a command injection vulnerability in the web user interface that could allow a remote, authenticated attacker to inject commands that can be executed as the root user.

Other sources

A vulnerability in the web UI of Cisco IOS XE Software could allow an authenticated, remote attacker to inject arbitrary commands that can be executed as the root user. This vulnerability is due to insufficient input validation. An attacker could exploit this vulnerability by sending a crafted request to the web UI of an affected device with arbitrary commands injected into a portion of the request. A successful exploit could allow the attacker to execute arbitrary commands as the root user.

Affected Software

37 affected components
cisco Cisco IOS XE Web UI
Cisco IOS XE=16.9.1
Cisco IOS XE=16.9.1a
Cisco IOS XE=16.9.1b
Cisco IOS XE=16.9.1c
Cisco IOS XE=16.9.1d
Cisco IOS XE=16.9.1s
Cisco IOS XE=16.9.2
Cisco IOS XE=16.9.2a
Cisco IOS XE=16.9.2s
Cisco IOS XE=16.9.3
Cisco IOS XE=16.9.3a
Cisco IOS XE=16.9.3h
Cisco IOS XE=16.9.3s
Cisco IOS XE=16.9.4
Cisco IOS XE=16.9.4c
Cisco IOS XE=16.9.5
Cisco IOS XE=16.9.5f
Cisco IOS XE=16.9.6
Cisco IOS XE=16.10.1
Cisco IOS XE=16.10.1a
Cisco IOS XE=16.10.1b
Cisco IOS XE=16.10.1c
Cisco IOS XE=16.10.1d
Cisco IOS XE=16.10.1e
Cisco IOS XE=16.10.1f
Cisco IOS XE=16.10.1g
Cisco IOS XE=16.10.1s
Cisco IOS XE=16.10.2
Cisco IOS XE=16.10.3
Cisco IOS XE=16.11.1
Cisco IOS XE=16.11.1a
Cisco IOS XE=16.11.1b
Cisco IOS XE=16.11.1c
Cisco IOS XE=16.11.1s
Cisco IOS XE=16.11.2
Cisco IOS XE=17.2.1v

Remediation

Information

Apply mitigations per vendor instructions or discontinue use of the product if mitigations are unavailable.

Event History

Mar 24, 2021
CVE Published
via MITRE·08:05 PM
Data Sourced
via MITRE·08:05 PM
DescriptionSeverityWeakness
Oct 16, 2023
News Published
via Dark Reading·08:44 PM
Oct 19, 2023
Known Exploited
12:00 AM
Dec 20, 2024
News Published
via Dark Reading·12:00 AM
Free Weekly Intel

Don't miss critical vulnerabilities

Join thousands of security professionals who receive our weekly digest of trending CVEs, zero-days, and exploited vulnerabilities.

No spam. Unsubscribe anytime.

Frequently Asked Questions

1

What is CVE-2021-1435?

CVE-2021-1435 is a vulnerability in the web UI of Cisco IOS XE Software that allows an authenticated, remote attacker to inject arbitrary commands as the root user.

2

How severe is CVE-2021-1435?

CVE-2021-1435 has a severity rating of 7.2, which is considered critical.

3

What software is affected by CVE-2021-1435?

Cisco IOS XE Web UI is affected by CVE-2021-1435.

4

How can an attacker exploit CVE-2021-1435?

An attacker can exploit CVE-2021-1435 by sending a crafted request to the web UI.

5

Are there any references for CVE-2021-1435?

Yes, you can find more information about CVE-2021-1435 at the following references: [Link 1](https://blog.talosintelligence.com/active-exploitation-of-cisco-ios-xe-software/), [Link 2](https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-iosxe-webcmdinjsh-UFJxTgZD)

Contact

SecAlerts Pty Ltd.
132 Wickham Terrace
Fortitude Valley,
QLD 4006, Australia
info@secalerts.co
By using SecAlerts services, you agree to our services end-user license agreement. This website is safeguarded by reCAPTCHA and governed by the Google Privacy Policy and Terms of Service. All names, logos, and brands of products are owned by their respective owners, and any usage of these names, logos, and brands for identification purposes only does not imply endorsement. If you possess any content that requires removal, please get in touch with us.
© 2026 SecAlerts Pty Ltd.
ABN: 70 645 966 203, ACN: 645 966 203