// For flags

CVE-2021-34791

Cisco Adaptive Security Appliance Software and Firepower Threat Defense Software Application Level Gateway Bypass Vulnerabilities

Severity Score

5.3
*CVSS v3.1

Exploit Likelihood

1%
*EPSS

Affected Versions

23
*CPE

Public Exploits

0
*Multiple Sources

Exploited in Wild

-
*KEV

Decision

Track
*SSVC
Descriptions

Multiple vulnerabilities in the Application Level Gateway (ALG) for the Network Address Translation (NAT) feature of Cisco Adaptive Security Appliance (ASA) Software and Firepower Threat Defense (FTD) Software could allow an unauthenticated, remote attacker to bypass the ALG and open unauthorized connections with a host located behind the ALG. For more information about these vulnerabilities, see the Details section of this advisory. Note: These vulnerabilities have been publicly discussed as NAT Slipstreaming.

Varias vulnerabilidades en la Puerta de Enlace de Nivel de Aplicación (ALG) para la funcionalidad Network Address Translation (NAT) del software Cisco Adaptive Security Appliance (ASA) y el software Firepower Threat Defense (FTD) podrían permitir a un atacante remoto no autenticado omitir la ALG y abrir conexiones no autorizadas con un host situado detrás de la ALG. Para conseguir más información sobre estas vulnerabilidades, consulte la sección Detalles de este aviso. Nota: Estas vulnerabilidades se han discutido públicamente como NAT Slipstreaming

*Credits: N/A
CVSS Scores
Attack Vector
Network
Attack Complexity
Low
Privileges Required
None
User Interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
Low
Availability
None
Attack Vector
Network
Attack Complexity
Low
Privileges Required
None
User Interaction
Required
Scope
Changed
Confidentiality
None
Integrity
Low
Availability
None
Attack Vector
Network
Attack Complexity
Low
Authentication
None
Confidentiality
None
Integrity
Partial
Availability
None
* Common Vulnerability Scoring System
SSVC
  • Decision:Track
Exploitation
None
Automatable
No
Tech. Impact
Partial
* Organization's Worst-case Scenario
Timeline
  • 2021-06-15 CVE Reserved
  • 2021-10-27 CVE Published
  • 2024-11-07 CVE Updated
  • 2025-03-30 EPSS Updated
  • ---------- Exploited in Wild
  • ---------- KEV Due Date
  • ---------- First Exploit
CWE
  • CWE-20: Improper Input Validation
  • CWE-358: Improperly Implemented Security Check for Standard
CAPEC
References (1)
Affected Vendors, Products, and Versions (23)