CVE-2021-1435Network attack vector

Root command execution via crafted web requests

Published Mar 24, 2021 · Updated Dec 16, 2025

Command injection in the Cisco IOS XE Software web UI allows remote authenticated users to execute arbitrary commands as root via crafted requests. The web UI insufficiently validates a request portion before passing injected command text for privileged execution. An affected device must run a vulnerable release with the web UI enabled; configured session-module exclusions block exploitation on the corresponding protocol.

CVSS severity6.6
Medium
EPSS probability8.09%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Command injection in the Cisco IOS XE Software web UI allows remote authenticated users to execute arbitrary commands as root via crafted requests. The web UI insufficiently validates a request portion before passing injected command text for privileged execution. An affected device must run a vulnerable release with the web UI enabled; configured session-module exclusions block exploitation on the corresponding protocol.

The record

CVE
CVE-2021-1435
Published
Mar 24, 2021
Updated
Dec 16, 2025
Vendor
ClamAV
Product
Cisco IOS XE Software
Classifications
CWE-22, T1190
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Mar 24, 2021CVE publishedPublication date reported by the CVE source.
  2. Dec 16, 2025Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=n/a

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

ClamAV · Cisco IOS XE Softwareversion=n/a

Published CVSS scores

7.2NIST NVDCVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H
6.6Cisco Systems, Inc.CVSS:3.0/AV:N/AC:H/PR:H/UI:N/S:U/C:H/I:H/A:H/E:X/RL:X/RC:X
9.0NIST NVDAV:N/AC:L/Au:S/C:C/I:C/A:C

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-22Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal')
T1190Exploit Public-Facing Application

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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