CVE-2021-34723

Root access via CLI parameter validation failure

Published Sep 23, 2021 · Updated Nov 7, 2024

Improper access control in Cisco IOS XE Software with SD-WAN enabled allows local users with high privileges to gain root access. A specific, undisclosed CLI command insufficiently validates supplied parameters before using them to overwrite arbitrary files in the configuration database. The feature is disabled by default, and successful exploitation corrupts configuration-database content while elevating the user's access to root.

CVSS severity6.7
Medium
EPSS probability0.24%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Improper access control in Cisco IOS XE Software with SD-WAN enabled allows local users with high privileges to gain root access. A specific, undisclosed CLI command insufficiently validates supplied parameters before using them to overwrite arbitrary files in the configuration database. The feature is disabled by default, and successful exploitation corrupts configuration-database content while elevating the user's access to root.

The record

CVE
CVE-2021-34723
Published
Sep 23, 2021
Updated
Nov 7, 2024
Vendor
ClamAV
Product
Cisco IOS XE Software
Classifications
CWE-668, T1068
Attack vector
local
Privileges
admin

Timeline

How it unfolded

  1. Sep 23, 2021CVE publishedPublication date reported by the CVE source.
  2. Nov 7, 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 vectorlocal
Required privilegesadmin

What is affected?

ClamAV · Cisco IOS XE Softwareversion=n/a

Published CVSS scores

6.9NIST NVDAV:L/AC:M/Au:N/C:C/I:C/A:C
6.7CiscoCVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H/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 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
Privilegesadmin
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-668Exposure of Resource to Wrong Sphere
T1068Exploitation for Privilege Escalation

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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