CVE-2021-1256
Cisco Firepower Threat Defense Software Command File Overwrite Vulnerability
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.
Attack profile
How easy it is to exploit
- Attack vector
- Local
- Complexity
- Low
- Privileges needed
- High
- User interaction
- None
What an attacker can affect
- Confidentiality
- None
- Integrity
- High
- Availability
- High
Exploit likelihood
What each source reports
CVE List Score used
6.0
Cisco Firepower Threat Defense Software Command File Overwrite Vulnerability
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.
- Record
CVE-2021-1256- CVSS 3.1
- 6.0 Medium
CVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:U/C:N/I:H/A:H - Weakness
- CWE-552
- Updated
- 2026-11-02
EUVDEUVD-2021-6723
6.0
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.
- Record
EUVD-2021-6723- CVSS 3.1
- 6.0 Medium
CVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:U/C:N/I:H/A:H - Updated
- 2026-11-03
GitHub AdvisoriesGHSA-x8wc-vwc8-w26v
6.0
A vulnerability in the CLI of Cisco Firepower Threat Defense (FTD) Software could allow an...
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.
- Record
GHSA-x8wc-vwc8-w26v- CVSS 3.1
- 6.0 Medium
CVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:U/C:N/I:H/A:H - Weakness
- CWE-22, CWE-552
- Updated
- 2026-11-02
NVD
6.0
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.
- Record
CVE-2021-1256- CVSS 3.1
- 6.0 Medium
CVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:U/C:N/I:H/A:H - CVSS 2.0
- 3.6 Low
AV:L/AC:L/Au:N/C:N/I:P/A:P - Weakness
- CWE-552, CWE-22
- Updated
- 2026-11-02
Affected products
History
| Recorded | Changed | Sources |
|---|---|---|
| aliases, published | EUVD | |
| first indexed | CVE List, GitHub Advisories, NVD |
Dates are when Every CVE recorded each change. Upstream dates may differ.
In short
CVE-2021-1256 is a medium vulnerability (CVSS 6.0) in Cisco Firepower Threat Defense Software, published April 29, 2021. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 0.50%, the 43rd percentile. No source names a fixed version.