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Adaptive Security Appliance Software CVE-2026-20073

MEDIUM
Improper Access Control (CWE-284)
2026-03-04 psirt@cisco.com
5.8
CVSS 3.1 · Vendor: cisco
View

Vulnerability Assessment

Weakness
CWE
OWASP Top 10:2025
A01:2025 - Broken Access Control
ASVS 5.0
V8 - Authorization Access control enforcement
MITRE ATT&CK

1 technique across 1 tactic: Defense Evasion

The technique list with ATT&CK links and the kill-chain view is part of the Basic plan and up.

Impact

CVSS 5.8 (MEDIUM). Attack vector: Network. Complexity: Low. Privileges required: None. User interaction: None. Exploitation no authentication required. Exploitable via remote/network.

Exploit ScenarioDerived

A remote attacker without authentication could exploit this vulnerability to bypass access controls and reach devices in protected networks.

This Month Plan within 30 days. Why: MEDIUM severity (CVSS 4.0-6.9).
No patch listed yet 0.1% exploitation probability (EPSS)

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AnalysisAIv1 – Mar 12, 2026

Unauthenticated remote attackers can bypass firewall access controls on Cisco Secure Firewall ASA and FTD devices by exploiting improper error handling during cluster memory exhaustion when syncing security rules. This allows attackers to send traffic that should be blocked through affected devices to reach protected networks. No patch is currently available.

Earlier versions of this analysis (1)
v1 Mar 12, 2026 - 22:05 CVSS 5.8

A vulnerability in Cisco Secure Firewall Adaptive Security Appliance (ASA) Software and Cisco Secure Firewall Threat Defense (FTD) Software could allow an unauthenticated, remote attacker to send traffic that should be denied through an affected device. [CVSS 5.8 MEDIUM]

RemediationAI

Monitor vendor advisories for a patch. Restrict network access to the affected service where possible.

Affects your stack

Find out whether the stacks and servers you run are on an affected version.

Checking this CVE against your own stacks and servers is part of the Basic plan and up.

Technical ContextAI · show details

Classified as CWE-284 (Improper Access Control). A vulnerability in Cisco Secure Firewall Adaptive Security Appliance (ASA) Software and Cisco Secure Firewall Threat Defense (FTD) Software could allow an unauthenticated, remote attacker to send traffic that should be denied through an affected device.

This vulnerability is due to improper error handling when an affected device that is joining a cluster runs out of memory while replicating access control rules. An attacker could exploit this vulnerability by sending traffic that should be bl

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  • Exploit and PoC references, threat intelligence from 22 sources

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Severity by source

Vendor (cisco) PRIMARY 5.8 MEDIUM
AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:L/A:N

Primary rating from Vendor (cisco) · only source for this CVE.

CVSS VectorVendor: cisco

Attack Vector
Network
Attack Complexity
Low
Privileges Required
None
User Interaction
None
Scope
Changed
Confidentiality
None
Integrity
Low
Availability
None

DescriptionCVE.org

A vulnerability in Cisco Secure Firewall Adaptive Security Appliance (ASA) Software and Cisco Secure Firewall Threat Defense (FTD) Software could allow an unauthenticated, remote attacker to send traffic that should be denied through an affected device.

This vulnerability is due to improper error handling when an affected device that is joining a cluster runs out of memory while replicating access control rules. An attacker could exploit this vulnerability by sending traffic that should be blocked through the device. A successful exploit could allow the attacker to bypass access controls and reach devices in protected networks.

Executive ViewAI

Why It Matters

CVE-2026-20073 presents moderate security risk, a improper access control vulnerability rated CVSS 5.8. Exploitation could compromise the security of affected deployments. Organizations should apply vendor updates when available and monitor for exploitation.

Business Impact: Low
Compensating Controls

Apply vendor patch. If patching is delayed: restrict network access and enable monitoring.

Threat Intelligence Overview

EPSS Score
0.1%
Top 80% exploitable
Data Quality
4 sources
Confidence: Medium

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.

SignalValue
Severity MEDIUM
CISA KEV No
Public POC No
EPSS 0.1%
Patch available No
Active threat No
Deciding rule
MEDIUM severity (CVSS 4.0-6.9)
What every action level means
Emergency Immediate action required. Criteria: CRITICAL + in CISA KEV (actively exploited) without patch, OR CRITICAL + EPSS > 30% without patch, OR CRITICAL + active threat signals without patch.
Act Now Prioritize within 24-48h. Criteria: in KEV with patch available, OR CRITICAL + public POC, OR HIGH + EPSS > 10%, OR CRITICAL + active threat, OR any CRITICAL severity.
This Week Schedule remediation this week. Criteria: HIGH severity (CVSS 7.0-8.9). Patch within normal change window.
This Month Plan within 30 days. Criteria: MEDIUM severity (CVSS 4.0-6.9), lower exploitation probability. Include in regular patch cycle.
Monitor Track and reassess. Criteria: LOW severity (CVSS 0.1-3.9), minimal exploitation risk. No immediate action needed.

SSVC AssessmentENISA

SSVC Decision· derived
Scheduled
Exploitation· derived
None
System Exposure· derived
Open
Automatable· derived
Yes
Human Impact
Low

Priority Score

29
Low Medium High Critical
KEV: 0
EPSS: 0
CVSS: +29
PoC: 0
Weaponized: 0
Threat intel: 0
Gov advisory: 0

Attack Technique

Authentication bypass attacks exploit flaws in the verification mechanisms that control access to systems and applications.

Affected Products (CPE)CVE.org

cpe:2.3:o:cisco:adaptive_security_appliance_software:9.12.1:*:*:*:*:*:*:*
cpe:2.3:o:cisco:adaptive_security_appliance_software:9.12.1.2:*:*:*:*:*:*:*
cpe:2.3:o:cisco:adaptive_security_appliance_software:9.12.1.3:*:*:*:*:*:*:*
cpe:2.3:o:cisco:adaptive_security_appliance_software:9.12.2:*:*:*:*:*:*:*
cpe:2.3:o:cisco:adaptive_security_appliance_software:9.12.2.1:*:*:*:*:*:*:*
cpe:2.3:o:cisco:adaptive_security_appliance_software:9.12.2.4:*:*:*:*:*:*:*
cpe:2.3:o:cisco:adaptive_security_appliance_software:9.12.2.5:*:*:*:*:*:*:*
cpe:2.3:o:cisco:adaptive_security_appliance_software:9.12.2.9:*:*:*:*:*:*:*
cpe:2.3:o:cisco:adaptive_security_appliance_software:9.12.3:*:*:*:*:*:*:*
cpe:2.3:o:cisco:adaptive_security_appliance_software:9.12.3.2:*:*:*:*:*:*:*
cpe:2.3:o:cisco:adaptive_security_appliance_software:9.12.3.7:*:*:*:*:*:*:*
cpe:2.3:o:cisco:adaptive_security_appliance_software:9.12.3.9:*:*:*:*:*:*:*
cpe:2.3:o:cisco:adaptive_security_appliance_software:9.12.3.12:*:*:*:*:*:*:*
cpe:2.3:o:cisco:adaptive_security_appliance_software:9.12.4:*:*:*:*:*:*:*
cpe:2.3:o:cisco:adaptive_security_appliance_software:9.12.4.2:*:*:*:*:*:*:*
cpe:2.3:o:cisco:adaptive_security_appliance_software:9.12.4.4:*:*:*:*:*:*:*
cpe:2.3:o:cisco:adaptive_security_appliance_software:9.12.4.7:*:*:*:*:*:*:*
cpe:2.3:o:cisco:adaptive_security_appliance_software:9.12.4.8:*:*:*:*:*:*:*
cpe:2.3:o:cisco:adaptive_security_appliance_software:9.12.4.10:*:*:*:*:*:*:*
cpe:2.3:o:cisco:adaptive_security_appliance_software:9.12.4.13:*:*:*:*:*:*:*
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