CVE-2021-34761

What it is

A vulnerability in Cisco Firepower Threat Defense (FTD) Software could allow an authenticated, local attacker to overwrite or append arbitrary data to system files using root-level privileges. The attacker must have administrative credentials on the device. This vulnerability is due to incomplete validation of user input for a specific CLI command. An attacker could exploit this vulnerability by authenticating to the device with administrative privileges and issuing a CLI command with crafted user parameters. A successful exploit could allow the attacker to overwrite or append arbitrary data to system files using root-level privileges.

At a glance

Exploitability

Can be exploited locally on the machine with an admin-level account. High risk of data tampering.

Exploit odds

0.2% chance of exploitation in the next 30 days (EPSS).

Fix

A patch, advisory or fixed version is referenced. Upgrade or apply it.

Timeline

1. 2021-10-27 19:15 UTC PublishedDisclosed publicly on CVE.org and NVD
2. 2026-08-11 19:33 UTC Last updatedMost recent change to the record

Why it ranks here

• Exploited in the wild: no, CISA does not list it.
• Exploit odds: 0.2% in the next 30 days (EPSS).
• Severity: 4.4 MEDIUM (CVSS).
• Fix: a patch or advisory is linked.

Details

Published

2021-10-27 19:15 UTC

Last modified

2026-08-11 19:33 UTC

Exploit probability

0.2% · EPSS, next 30 days

Weakness

CWE-73

Record status

Modified

Affected

• Cisco Firepower Management Center Virtual Appliance 6.2.3
• Cisco Firepower Management Center Virtual Appliance 6.4.0
• Cisco Firepower Management Center Virtual Appliance 6.6.1
• Cisco Firepower Management Center Virtual Appliance 6.7.0
• Cisco Firepower Management Center Virtual Appliance 7.0.0
• Cisco Firepower Management Center Virtual Appliance 7.1.0
• Cisco Secure Firewall Threat Defense < 6.4.0.13
• Cisco Secure Firewall Threat Defense < 6.6.5

Attack profile CVSS 3.1 · 4.4

Attack vector

Local

Complexity

Low

Privileges needed

High

User interaction

None

Scope

Unchanged

Confidentiality

None

Integrity

High

Availability

None

Is it in your code?

Hand this to your coding agent. It searches your project for the affected products and checks versions. Nothing leaves your machine.

Read https://cve-list.com/agent/cve/CVE-2021-34761.md and follow it. Check whether this project is affected by CVE-2021-34761. Read only. Don't change anything and don't upload my code. Tell me yes, no or not sure, with the file as proof.

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