CVE-2021-34761

Arbitrary file write via malformed CLI parameters

Published Oct 27, 2021 · Updated Nov 7, 2024

Arbitrary file write in Cisco Firepower Threat Defense Software allows local users with administrative credentials to alter system files. A specific CLI command incompletely validates crafted user parameters before passing them to a root-privileged file operation; Cisco has not named the command. Administrative device credentials and local CLI access are required, and successful exploitation overwrites or appends attacker-chosen data.

CVSS severity4.4
Medium
EPSS probability0.21%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Arbitrary file write in Cisco Firepower Threat Defense Software allows local users with administrative credentials to alter system files. A specific CLI command incompletely validates crafted user parameters before passing them to a root-privileged file operation; Cisco has not named the command. Administrative device credentials and local CLI access are required, and successful exploitation overwrites or appends attacker-chosen data.

The record

CVE
CVE-2021-34761
Published
Oct 27, 2021
Updated
Nov 7, 2024
Vendor
ClamAV
Product
Cisco Firepower Threat Defense Software
Classifications
CWE-668, CWE-73, T1565.001
Attack vector
local
Privileges
admin

Timeline

How it unfolded

  1. Oct 27, 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 Firepower Threat Defense Softwareversion=n/a

Published CVSS scores

6.6NIST National Vulnerability DatabaseAV:L/AC:L/Au:N/C:N/I:C/A:C
6.0NIST National Vulnerability DatabaseCVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:U/C:N/I:H/A:H
4.4Cisco Systems, Inc.CVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:U/C:N/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 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
CWE-73External Control of File Name or Path
T1565.001Stored Data Manipulation

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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