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Vulnerability record · CVE-2020-3283 · published 6 May 2020

CVE-2020-3283: Cisco secure firewall threat defense memory buffer overflow vulnerability

Cisco · Secure Firewall Threat Defense

A vulnerability in the Secure Sockets Layer (SSL)/Transport Layer Security (TLS) handler of Cisco Firepower Threat Defense (FTD) Software when running on the Cisco Firepower 1000 Series platform could allow an unauthenticated, remote attacker to trigger a denial of service (DoS) condition on an affected device. The vulnerability is due to a communication error between internal functions. 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 a buffer underrun, which leads to a crash. The crash causes the affected device to reload.

8.6 CVSS 3.1 High EPSS 2.0% · top 20.0% CWE-119 · Memory buffer overflowCWE-787 · Out-of-bounds write
8.6CVSS 3.1 base score, v2 5.0
2.0%EPSS exploitation probability, 30 days
NoNot in CISA KEV
13Affected product versions listed by NVD
2References
11 Aug 2026Last modified by NVD

Description

A vulnerability in the Secure Sockets Layer (SSL)/Transport Layer Security (TLS) handler of Cisco Firepower Threat Defense (FTD) Software when running on the Cisco Firepower 1000 Series platform could allow an unauthenticated, remote attacker to trigger a denial of service (DoS) condition on an affected device. The vulnerability is due to a communication error between internal functions. 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 a buffer underrun, which leads to a crash. The crash causes the affected device to reload.

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

Affected products

13 vulnerable configurations from NVD's CPE data, grouped by vendor and product.

References

LinkTags
https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-ftd-tls-dos-4v5nmWtZ Vendor Advisory
https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-ftd-tls-dos-4v5nmWtZ Vendor Advisory

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Related vulnerabilities

Same products first, then exploited flaws of the same weakness class.

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Source: NIST National Vulnerability Database (record CVE-2020-3283), CISA KEV, FIRST EPSS (scores of 2026-09-27). This page is refreshed as NVD updates the record.