CVE-2021-34718Network attack vector

Arbitrary file read/write via SCP argument injection

Published Sep 9, 2021 · Updated Nov 7, 2024

Argument injection in Cisco IOS XR Software before 7.3.2 and 7.4.1 allows remote authenticated users to read and write arbitrary files. The SSH Server accepts insufficiently validated SCP arguments, letting lower-privilege accounts redirect file-transfer operations to unauthorized paths. Exploitation requires authenticated network access and can expose or alter device files and enable privilege escalation, but does not directly interrupt availability.

CVSS severity8.1
High
EPSS probability1.58%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Argument injection in Cisco IOS XR Software before 7.3.2 and 7.4.1 allows remote authenticated users to read and write arbitrary files. The SSH Server accepts insufficiently validated SCP arguments, letting lower-privilege accounts redirect file-transfer operations to unauthorized paths. Exploitation requires authenticated network access and can expose or alter device files and enable privilege escalation, but does not directly interrupt availability.

The record

CVE
CVE-2021-34718
Published
Sep 9, 2021
Updated
Nov 7, 2024
Vendor
ClamAV
Product
Cisco IOS XR Software
Classifications
CWE-88, T1210
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Sep 9, 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 vectornetwork
Required privilegesauthenticated

What is affected?

ClamAV · Cisco IOS XR Softwareversion=n/a

Published CVSS scores

8.5NVDAV:N/AC:L/Au:S/C:C/I:C/A:N
8.1NVDCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N
8.1Cisco Systems, Inc.CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N

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-88Improper Neutralization of Argument Delimiters in a Command ('Argument Injection')
T1210Exploitation of Remote Services

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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