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Case File

CVE-2021-34781

HIGH · CVSS 8.6 EPSS 1.35% Public Exploit

Source: NVD + CISA KEV + EPSS (historical backfill) · Published 2021-10-27 · Last synced 2026-08-04

CyberRota Analysis

This is a high severity vulnerability with a CVSS score of 8.6. It affects Cisco. Public exploit code or proof-of-concept references have been detected in its references. It may be remotely exploitable. It may lead to a denial-of-service condition.

Public Exploit Signal

A public exploit, PoC, GitHub repository or Metasploit reference was detected for this CVE.

Detected Signals
exploit

Note: these links are listed for security research and verification purposes only.

CVE
CVE-2021-34781
Severity
HIGH
CVSS
8.6
EPSS
1.35%
Cisco

Original NVD Description

A vulnerability in the processing of SSH connections for multi-instance deployments of Cisco Firepower Threat Defense (FTD) Software could allow an unauthenticated, remote attacker to cause a denial of service (DoS) condition on the affected device. This vulnerability is due to a lack of proper error handling when an SSH session fails to be established. An attacker could exploit this vulnerability by sending a high rate of crafted SSH connections to the instance. A successful exploit could allow the attacker to cause resource exhaustion, which causes a DoS condition on the affected device. The device must be manually reloaded to recover.

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