CVE-2026-20103

A vulnerability in the Remote Access SSL VPN functionality of Cisco Secure Firewall Adaptive Security Appliance (ASA) Software and Secure Firewall Threat Defense (FTD) Software could allow an unauthenticated, remote attacker to exhaust device memory resulting in a denial of service (DoS) condition to new Remote Access SSL VPN connections. This does not affect the management interface, though it may become temporarily unresponsive. This vulnerability is due to trusting user input without validation. An attacker could exploit this vulnerability by sending crafted packets to the Remote Access SSL VPN server. A successful exploit could allow the attacker to cause the device web interface to stop responding, resulting in a DoS condition.

Published: 2026-03-04 Last update: 2026-04-16 Assigner: [email protected] Source: [email protected]
NVD Status：Analyzed，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2026-20103 is rated Low Risk (39.8/100): CVSS High severity, with low exploitation likelihood (EPSS 0.05%). Monitor for updates and reassess as exploit intelligence or EPSS changes.

Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.

Exploit prediction scoring system (EPSS) score for CVE-2026-20103

EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).

# Date Old EPSS score New EPSS score Delta (New - Old)
1 2026-03-05 — 0.05% —

Full EPSS history (1 record total)

Common vulnerability scoring system (CVSS) metrics for CVE-2026-20103

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
8.6 3.1 HIGH
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:N)
No account or special rights needed—anonymous or random user is enough.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:C)
Breaking this can reach past the original component and bite other resources—bigger blast radius.
Confidentiality (C:N)
Doesn’t really leak secrets in a meaningful way.
Integrity (I:N)
Data isn’t meaningfully altered or forged.
Availability (A:H)
Could take the service down hard or make it unusable for people who depend on it.
 3.9 4.0 [email protected]

Weakness enumeration for CVE-2026-20103

Affected software / configurations for CVE-2026-20103

Vendor Product Version Raw CPE
cisco adaptive_security_appliance_software >= 9.12.1, < 9.16.4.85 cpe:2.3:o:cisco:adaptive_security_appliance_software:*:*:*:*:*:*:*:*
cisco adaptive_security_appliance_software >= 9.17.1, < 9.18.4.66 cpe:2.3:o:cisco:adaptive_security_appliance_software:*:*:*:*:*:*:*:*
cisco adaptive_security_appliance_software >= 9.19.1, < 9.20.4 cpe:2.3:o:cisco:adaptive_security_appliance_software:*:*:*:*:*:*:*:*
cisco adaptive_security_appliance_software >= 9.22.1.1, < 9.22.2.4 cpe:2.3:o:cisco:adaptive_security_appliance_software:*:*:*:*:*:*:*:*
cisco adaptive_security_appliance_software >= 9.23.1, < 9.23.1.7 cpe:2.3:o:cisco:adaptive_security_appliance_software:*:*:*:*:*:*:*:*
cisco firepower_threat_defense_software >= 6.4.0, < 7.0.9 cpe:2.3:a:cisco:firepower_threat_defense_software:*:*:*:*:*:*:*:*
cisco firepower_threat_defense_software >= 7.1.0, < 7.2.11 cpe:2.3:a:cisco:firepower_threat_defense_software:*:*:*:*:*:*:*:*
cisco firepower_threat_defense_software >= 7.3.0, < 7.4.3 cpe:2.3:a:cisco:firepower_threat_defense_software:*:*:*:*:*:*:*:*
cisco firepower_threat_defense_software >= 7.6.0, < 7.6.4 cpe:2.3:a:cisco:firepower_threat_defense_software:*:*:*:*:*:*:*:*
cisco firepower_threat_defense_software >= 7.7.0, < 7.7.11 cpe:2.3:a:cisco:firepower_threat_defense_software:*:*:*:*:*:*:*:*

References for CVE-2026-20103

cvelogic Threat Intelligence