How severe is CVE-2021-34792?

CVE-2021-34792 has a CVSS 3.x base score of 8.6, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity none, and availability high.

Is CVE-2021-34792 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (69th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2021-34792?

CVE-2021-34792 primarily affects Cisco Firepower Threat Defense. In total, 34 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2021-34792?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.

When was CVE-2021-34792 published?

CVE-2021-34792 was published on 2021-10-27 and last updated on 2026-06-17.

CVE-2021-34792

CVE-2021-34792 is a high-severity vulnerability in Cisco Firepower Threat Defense with a CVSS 3.x base score of 8.6. 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-401.

Key facts

Severity: High (CVSS 3.x base score 8.6)
CVSS v2: 7.8
EPSS exploit prediction: 1% (69th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-401
Affected product: Cisco Firepower Threat Defense
Published: 2021-10-27
Last modified: 2026-06-17

Description

A vulnerability in the memory management of Cisco Adaptive Security Appliance (ASA) Software and Firepower Threat Defense (FTD) Software could allow an unauthenticated, remote attacker to cause a denial of service (DoS) condition on an affected device. This vulnerability is due to improper resource management when connection rates are high. An attacker could exploit this vulnerability by opening a significant number of connections on an affected device. A successful exploit could allow the attacker to cause the device to reload, resulting in a DoS condition.

Frequently asked questions

What is CVE-2021-34792?: A vulnerability in the memory management of Cisco Adaptive Security Appliance (ASA) Software and Firepower Threat Defense (FTD) Software could allow an unauthenticated, remote attacker to cause a denial of service (DoS) condition on an affected device. This vulnerability is due to improper resource management when connection rates are high. An attacker could exploit this vulnerability by opening a significant number of connections on an affected device. A successful exploit could allow the attacker to cause the device to reload, resulting in a DoS condition.
How severe is CVE-2021-34792?: CVE-2021-34792 has a CVSS 3.x base score of 8.6, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity none, and availability high.
Is CVE-2021-34792 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (69th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2021-34792?: CVE-2021-34792 primarily affects Cisco Firepower Threat Defense. In total, 34 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2021-34792?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
When was CVE-2021-34792 published?: CVE-2021-34792 was published on 2021-10-27 and last updated on 2026-06-17.

References

https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-asa-ftd-dos-Unk689XY

Affected products (34)

cpe:2.3:a:cisco:firepower_threat_defense:*:*:*:*:*:*:*:*
cpe:2.3:o:cisco:adaptive_security_appliance_software:*:*:*:*:*:*:*:*
cpe:2.3:o:cisco:asa_5512-x_firmware:009.014\(001.150\):*:*:*:*:*:*:*
cpe:2.3:o:cisco:asa_5512-x_firmware:099.017\(001.211\):*:*:*:*:*:*:*
cpe:2.3:o:cisco:asa_5512-x_firmware:099.017\(001.220\):*:*:*:*:*:*:*
cpe:2.3:o:cisco:asa_5512-x_firmware:099.017\(015.050\):*:*:*:*:*:*:*
cpe:2.3:o:cisco:asa_5505_firmware:009.014\(001.150\):*:*:*:*:*:*:*
cpe:2.3:o:cisco:asa_5505_firmware:099.017\(001.211\):*:*:*:*:*:*:*
cpe:2.3:o:cisco:asa_5505_firmware:099.017\(001.220\):*:*:*:*:*:*:*
cpe:2.3:o:cisco:asa_5505_firmware:099.017\(015.050\):*:*:*:*:*:*:*
cpe:2.3:o:cisco:asa_5515-x_firmware:009.014\(001.150\):*:*:*:*:*:*:*
cpe:2.3:o:cisco:asa_5515-x_firmware:099.017\(001.211\):*:*:*:*:*:*:*
cpe:2.3:o:cisco:asa_5515-x_firmware:099.017\(001.220\):*:*:*:*:*:*:*
cpe:2.3:o:cisco:asa_5515-x_firmware:099.017\(015.050\):*:*:*:*:*:*:*
cpe:2.3:o:cisco:asa_5525-x_firmware:009.014\(001.150\):*:*:*:*:*:*:*
cpe:2.3:o:cisco:asa_5525-x_firmware:099.017\(001.211\):*:*:*:*:*:*:*
cpe:2.3:o:cisco:asa_5525-x_firmware:099.017\(001.220\):*:*:*:*:*:*:*
cpe:2.3:o:cisco:asa_5525-x_firmware:099.017\(015.050\):*:*:*:*:*:*:*
cpe:2.3:o:cisco:asa_5545-x_firmware:009.014\(001.150\):*:*:*:*:*:*:*
cpe:2.3:o:cisco:asa_5545-x_firmware:099.017\(001.211\):*:*:*:*:*:*:*
cpe:2.3:o:cisco:asa_5545-x_firmware:099.017\(001.220\):*:*:*:*:*:*:*
cpe:2.3:o:cisco:asa_5545-x_firmware:099.017\(015.050\):*:*:*:*:*:*:*
cpe:2.3:o:cisco:asa_5555-x_firmware:009.014\(001.150\):*:*:*:*:*:*:*
cpe:2.3:o:cisco:asa_5555-x_firmware:099.017\(001.211\):*:*:*:*:*:*:*
cpe:2.3:o:cisco:asa_5555-x_firmware:099.017\(001.220\):*:*:*:*:*:*:*
cpe:2.3:o:cisco:asa_5555-x_firmware:099.017\(015.050\):*:*:*:*:*:*:*
cpe:2.3:o:cisco:asa_5580_firmware:009.014\(001.150\):*:*:*:*:*:*:*
cpe:2.3:o:cisco:asa_5580_firmware:099.017\(001.211\):*:*:*:*:*:*:*
cpe:2.3:o:cisco:asa_5580_firmware:099.017\(001.220\):*:*:*:*:*:*:*
cpe:2.3:o:cisco:asa_5580_firmware:099.017\(015.050\):*:*:*:*:*:*:*
cpe:2.3:o:cisco:asa_5585-x_firmware:009.014\(001.150\):*:*:*:*:*:*:*
cpe:2.3:o:cisco:asa_5585-x_firmware:099.017\(001.211\):*:*:*:*:*:*:*
cpe:2.3:o:cisco:asa_5585-x_firmware:099.017\(001.220\):*:*:*:*:*:*:*
cpe:2.3:o:cisco:asa_5585-x_firmware:099.017\(015.050\):*:*:*:*:*:*:*

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