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CVE-2021-34783

HIGHCVSS 7.5/10EPSS 1.55%

Last modified

CVE-2021-34783 is a high-severity vulnerability rated 7.5/10 on the CVSS scale. A vulnerability in the software-based SSL/TLS message handler of Cisco Adaptive Security Appliance (ASA) Software and Firepower Threat Defense (FTD) Software could allow an unauthenticated, remote attacker to cause an affected device to reload, resulting in a denial of service (DoS) condition. This vulnerability is due to insufficient validation of SSL/TLS messages when the device performs software-based SSL/TLS decryption. EPSS estimates a 1.55% chance of exploitation in the next 30 days.

Description

A vulnerability in the software-based SSL/TLS message handler of Cisco Adaptive Security Appliance (ASA) Software and Firepower Threat Defense (FTD) Software could allow an unauthenticated, remote attacker to cause an affected device to reload, resulting in a denial of service (DoS) condition. This vulnerability is due to insufficient validation of SSL/TLS messages when the device performs software-based SSL/TLS decryption. An attacker could exploit this vulnerability by sending a crafted SSL/TLS message to an affected device. A successful exploit could allow the attacker to cause the affected device to reload, resulting in a DoS condition. Note: Datagram TLS (DTLS) messages cannot be used to exploit this vulnerability.

Metrics

CVSS 3.1
7.5/10

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

EPSS Probability
1.55%

71.9th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

Affected Software

VendorProductVersions
CiscoFirepower Threat Defense>= 6.4.0, < 6.4.0.13
CiscoFirepower Threat Defense>= 6.6.0, < 6.6.5
CiscoFirepower Threat Defense>= 6.7.0, < 6.7.0.3
CiscoFirepower Threat Defense>= 7.0.0, < 7.0.1
CiscoAdaptive Security Appliance Software>= 9.8.0, < 9.8.4.40
CiscoAdaptive Security Appliance Software>= 9.12.0, < 9.12.4.29
CiscoAdaptive Security Appliance Software>= 9.14.0, < 9.14.3.9
CiscoAdaptive Security Appliance Software>= 9.15.0, < 9.15.1.17
CiscoAdaptive Security Appliance Software>= 9.16.0, < 9.16.2
CiscoAsa 5512-X Firmware009.016\(001\)
CiscoAsa 5512-X Firmware009.016\(001.025\)
CiscoAsa 5505 Firmware009.016\(001\)
CiscoAsa 5505 Firmware009.016\(001.025\)
CiscoAsa 5515-X Firmware009.016\(001\)
CiscoAsa 5515-X Firmware009.016\(001.025\)
CiscoAsa 5525-X Firmware009.016\(001\)
CiscoAsa 5525-X Firmware009.016\(001.025\)
CiscoAsa 5545-X Firmware009.016\(001\)
CiscoAsa 5545-X Firmware009.016\(001.025\)
CiscoAsa 5555-X Firmware009.016\(001\)
CiscoAsa 5555-X Firmware009.016\(001.025\)
CiscoAsa 5580 Firmware009.016\(001\)
CiscoAsa 5580 Firmware009.016\(001.025\)
CiscoAsa 5585-X Firmware009.016\(001\)
CiscoAsa 5585-X Firmware009.016\(001.025\)

References

Timeline

Published
Last Modified
Status
Modified

Frequently Asked Questions

What is CVE-2021-34783?
A vulnerability in the software-based SSL/TLS message handler of Cisco Adaptive Security Appliance (ASA) Software and Firepower Threat Defense (FTD) Software could allow an unauthenticated, remote attacker to cause an affected device to reload, resulting in a denial of service (DoS) condition. This vulnerability is due to insufficient validation of SSL/TLS messages when the device performs software-based SSL/TLS decryption. An attacker could exploit this vulnerability by sending a crafted SSL/TLS message to an affected device. A successful exploit could allow the attacker to cause the affected device to reload, resulting in a DoS condition. Note: Datagram TLS (DTLS) messages cannot be used to exploit this vulnerability.
How severe is CVE-2021-34783?
CVE-2021-34783 has a CVSS score of 7.5/10 (HIGH severity). The EPSS model estimates a 1.55% probability of exploitation in the next 30 days.
How do I fix CVE-2021-34783?
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-2021-34783?

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

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Source: NVD / NIST