CVE-2021-1256

CVE-2021-1256 is a medium-severity vulnerability in Cisco Secure Firewall Threat Defense with a CVSS 3.x base score of 6.0. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-22.

Key facts

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.

Frequently asked questions

What is CVE-2021-1256?
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.
How severe is CVE-2021-1256?
CVE-2021-1256 has a CVSS 3.x base score of 6.0, rated medium severity. It is exploitable over local access with low attack complexity, requires high privileges and no user interaction. Impact on confidentiality is none, integrity high, and availability high.
Is CVE-2021-1256 being actively exploited?
It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (41st percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2021-1256?
CVE-2021-1256 affects Cisco Secure Firewall Threat Defense. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2021-1256?
Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
When was CVE-2021-1256 published?
CVE-2021-1256 was published on 2021-04-29 and last updated on 2026-08-11.

References

Affected products (1)

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