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CVE-2021-34791

MEDIUMCVSS 5.3/10EPSS 1.10%

Last modified

CVE-2021-34791 is a medium-severity vulnerability rated 5.3/10 on the CVSS scale. 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. EPSS estimates a 1.10% chance of exploitation in the next 30 days.

Description

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.

Metrics

CVSS 3.1
5.3/10

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N

EPSS Probability
1.10%

61.5th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

Affected Software

VendorProductVersions
CiscoAdaptive Security Appliance< 9.8.4.40
CiscoFirepower Threat Defense< 6.4.0.12
CiscoFirepower Threat Defense>= 6.5.0, < 6.6.5
CiscoFirepower Threat Defense>= 6.7.0, < 6.7.0.2
CiscoAdaptive Security Appliance Software>= 9.12.0, < 9.12.4.18
CiscoAdaptive Security Appliance Software>= 9.13.0, < 9.14.2.15
CiscoAdaptive Security Appliance Software>= 9.15.0, < 9.15.1.15
CiscoAsa 5512-X Firmware009.008
CiscoAsa 5512-X Firmware009.015
CiscoAsa 5505 Firmware009.008
CiscoAsa 5505 Firmware009.015
CiscoAsa 5515-X Firmware009.008
CiscoAsa 5515-X Firmware009.015
CiscoAsa 5525-X Firmware009.008
CiscoAsa 5525-X Firmware009.015
CiscoAsa 5545-X Firmware009.008
CiscoAsa 5545-X Firmware009.015
CiscoAsa 5555-X Firmware009.008
CiscoAsa 5555-X Firmware009.015
CiscoAsa 5580 Firmware009.008
CiscoAsa 5580 Firmware009.015
CiscoAsa 5585-X Firmware009.008
CiscoAsa 5585-X Firmware009.015

References

Timeline

Published
Last Modified
Status
Modified

Frequently Asked Questions

What is CVE-2021-34791?
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.
How severe is CVE-2021-34791?
CVE-2021-34791 has a CVSS score of 5.3/10 (MEDIUM severity). The EPSS model estimates a 1.10% probability of exploitation in the next 30 days.
How do I fix CVE-2021-34791?
Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

Are you affected by CVE-2021-34791?

Run a free Strix scan to check your systems for this vulnerability.

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Source: NVD / NIST