CVE-2021-1384Public exploitNetwork attack vector

Root command execution via unsanitized DNS parameter

Published Mar 24, 2021 · Updated Nov 8, 2024

Command injection in Cisco IOx for Cisco IOS XE Software allows remote authenticated users to execute operating-system commands as root. During container activation, the IOx DNS parameter is concatenated without sanitization into a shell command that writes /etc/resolv.conf. Administrative API access and nondefault IOx enablement are required to load and activate a crafted application package.

CVSS severity6.5
Medium
EPSS probability35.39%
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 Cisco IOx for Cisco IOS XE Software allows remote authenticated users to execute operating-system commands as root. During container activation, the IOx DNS parameter is concatenated without sanitization into a shell command that writes /etc/resolv.conf. Administrative API access and nondefault IOx enablement are required to load and activate a crafted application package.

The record

CVE
CVE-2021-1384
Published
Mar 24, 2021
Updated
Nov 8, 2024
Vendor
ClamAV
Product
Cisco IOS XE Software
Classifications
CWE-77, CWE-78, T1059.004
Attack vector
network
Privileges
admin

Timeline

How it unfolded

  1. Mar 24, 2021CVE publishedPublication date reported by the CVE source.
  2. Nov 8, 2024Record 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 privilegesadmin

What is affected?

ClamAV · Cisco IOS XE Softwareversion=n/a

Published CVSS scores

7.2NISTCVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H
8.5NISTAV:N/AC:M/Au:S/C:C/I:C/A:C
6.5Cisco Systems, Inc.CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:N/E:X/RL:X/RC:X

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 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesadmin
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-77Improper Neutralization of Special Elements used in a Command ('Command Injection')
CWE-78Improper Neutralization of Special Elements used in an OS Command ('OS Command Injection')
T1059.004Unix Shell

Public exploit references

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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