Adaptive Security Appliance Software
CVE-2026-20021
MEDIUM
Vulnerability Assessment
| Weakness |
CWE
OWASP Top 10:2025
A06:2021 - Vulnerable and Outdated Components
ASVS 5.0
V15 - Secure Coding and Architecture Resource cleanup, leak prevention
|
| Impact | CVSS 4.3 (MEDIUM). Attack vector: Adjacent Network. Complexity: Low. Privileges required: None. User interaction: None. Exploitation requires authentication. |
| Exploit ScenarioDerived | An attacker (requires authentication) could exploit this vulnerability to exhaust memory on the affected device, resulting in a DoS condition. |
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Alert meAnalysisAIv1 – Mar 12, 2026
Memory exhaustion in Cisco ASA and FTD OSPF protocol implementation allows adjacent authenticated attackers to trigger denial of service by sending specially crafted packets that bypass input validation. An attacker with network access to the affected device can exploit improper packet parsing to consume available memory and crash the appliance. No patch is currently available for this vulnerability.
Earlier versions of this analysis (1)
A vulnerability in the OSPF protocol of Cisco Secure Firewall Adaptive Security Appliance (ASA) Software and Cisco Secure Firewall Threat Defense (FTD) Software could allow an authenticated, adjacent attacker to exhaust memory on an affected device, resulting in a denial of service (DoS) condition. [CVSS 4.3 MEDIUM]
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Affects your stack
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Technical ContextAI · show details
Classified as CWE-401 (Memory Leak). A vulnerability in the OSPF protocol of Cisco Secure Firewall Adaptive Security Appliance (ASA) Software and Cisco Secure Firewall Threat Defense (FTD) Software could allow an authenticated, adjacent attacker to exhaust memory on an affected device, resulting in a denial of service (DoS) condition. This vulnerability is due to improperly validating input by the OSPF protocol when parsing packets. An attacker could exploit this vulnerability by by sending crafted OSPF packets to an affected de
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Severity by source
AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L
Primary rating from Vendor (cisco) · only source for this CVE.
CVSS VectorVendor: cisco
DescriptionCVE.org
A vulnerability in the OSPF protocol of Cisco Secure Firewall Adaptive Security Appliance (ASA) Software and Cisco Secure Firewall Threat Defense (FTD) Software could allow an authenticated, adjacent attacker to exhaust memory on an affected device, resulting in a denial of service (DoS) condition. This vulnerability is due to improperly validating input by the OSPF protocol when parsing packets. An attacker could exploit this vulnerability by by sending crafted OSPF packets to an affected device. A successful exploit could allow the attacker to exhaust memory on the affected device, resulting in a DoS condition.
Executive ViewAI
CVE-2026-20021 presents moderate security risk rated CVSS 4.3. Exploitation could compromise the security of affected deployments. Organizations should apply vendor updates when available and monitor for exploitation.
Apply vendor patch. If patching is delayed: restrict network access and enable monitoring.
Threat Intelligence Overview
NVD
CVE.org
EPSS
VulDB
How this decision was reached
The engine reads each signal below and applies a fixed list of rules from top to bottom. The first rule that matches sets the recommended action – like a statement, every line is shown.
What every action level means
SSVC AssessmentENISA
Priority Score
Attack Technique
Denial of Service attacks render applications or systems unavailable by overwhelming resources or triggering failure conditions.
Affected Products (CPE)CVE.org
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GitHub PoC
Exploit-DB