Adaptive Security Appliance Software
CVE-2026-20020
MEDIUM
Vulnerability Assessment
| Weakness |
CWE
OWASP Top 10:2025
A05:2025 - Injection
ASVS 5.0
V2 - Validation and Business Logic Input validation, allowlisting
|
| Impact | CVSS 6.8 (MEDIUM). Attack vector: Adjacent Network. Complexity: Low. Privileges required: Low. User interaction: None. Exploitation no authentication required. |
| Exploit ScenarioDerived | An attacker without authentication could exploit this vulnerability to create a buffer overflow, causing the affected device to reload, resulting in a. |
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Alert meAnalysisAIv1 – Mar 12, 2026
Insufficient input validation in Cisco Secure Firewall ASA and Secure FTD OSPF implementations allows adjacent attackers to trigger denial of service by sending malformed OSPF update packets that cause device reloads. Authentication bypass is possible if OSPF authentication is disabled, though knowing the secret key is required when authentication is enabled. No patch is currently available for this medium-severity vulnerability.
Earlier versions of this analysis (1)
OSPF protocol of Cisco Secure Firewall ASA Software and Cisco Secure FTD Software is affected by improper input validation (CVSS 6.8).
RemediationAI
Monitor vendor advisories for a patch. Enable ASLR, DEP/NX, and stack canaries where possible.
Affects your stack
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Technical ContextAI · show details
This vulnerability (CWE-20: Improper Input Validation) affects OSPF protocol of Cisco Secure Firewall ASA Software and Cisco Secure FTD Software. in the OSPF protocol of Cisco Secure Firewall ASA Software and Cisco Secure FTD Software could allow an unauthenticated, adjacent attacker to cause an affected device to reload unexpectedly, resulting in a DoS condition. If OSPF authentication is enabled, the attacker must know the secret key to exploit this vulnerability. This vulnerability is due to insufficient input validation when processing OSPF update packets. An attacker could exploit this vulnerability by sending crafted OSPF update
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Severity by source
AV:A/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
Primary rating from NVD · only source for this CVE.
CVSS VectorNVD
Lifecycle Timeline
2DescriptionNVD
A vulnerability in the OSPF protocol of Cisco Secure Firewall ASA Software and Cisco Secure FTD Software could allow an unauthenticated, adjacent attacker to cause an affected device to reload unexpectedly, resulting in a DoS condition. If OSPF authentication is enabled, the attacker must know the secret key to exploit this vulnerability. This vulnerability is due to insufficient input validation when processing OSPF update packets. An attacker could exploit this vulnerability by sending crafted OSPF update packets. A successful exploit could allow the attacker to create a buffer overflow, causing the affected device to reload, resulting in a DoS condition.
Executive ViewAI
CVE-2026-20020 presents notable security risk, a input validation vulnerability rated CVSS 6.8. 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: deploy WAF rules, restrict network access, enable logging.
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
A buffer overflow occurs when a program writes more data to a memory buffer than it was allocated to hold, causing the excess data to spill into adjacent memory regions.
Affected Products (CPE)NVD
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GitHub PoC
Exploit-DB