CVE-2021-1256: Cisco Firepower Threat Defense Software Command File Overwrite Vulnerability

Severity: medium (CVSS 6.0 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.5% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2021-04-29 · updated 2026-08-11
Weakness: CWE-552

Description

A vulnerability in the CLI of Cisco Firepower Threat Defense (FTD) Software could allow an authenticated, local attacker to overwrite files on the file system of an affected device by using directory traversal techniques. A successful exploit could cause system instability if important system files are overwritten. This vulnerability is due to insufficient validation of user input for the file path in a specific CLI command. An attacker could exploit this vulnerability by logging in to a targeted device and issuing a specific CLI command with crafted user input. A successful exploit could allow the attacker to overwrite arbitrary files on the file system of the affected device. The attacker would need valid user credentials on the device.

Affected products

Cisco Firepower Threat Defense Software: through 6.4.0; from 6.6.0 before 6.6.4 — fixed in 6.6.4

How to fix

Upgrade to a fixed version: Cisco Firepower Threat Defense Software 6.6.4. Check the vendor advisory for mitigations.

References

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