What’s Vulnerable › Vulnerabilities

CVE-2021-1312: Cisco Elastic Services Controller Denial of Service Vulnerability

• Severity: high (CVSS 7.5 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 2.6% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2021-01-20 · updated 2026-06-17
• Weakness: CWE-400

Description

A vulnerability in the system resource management of Cisco Elastic Services Controller (ESC) could allow an unauthenticated, remote attacker to cause a denial of service (DoS) to the health monitor API on an affected device. The vulnerability is due to inadequate provisioning of kernel parameters for the maximum number of TCP connections and SYN backlog. An attacker could exploit this vulnerability by sending a flood of crafted TCP packets to an affected device. A successful exploit could allow the attacker to block TCP listening ports that are used by the health monitor API. This vulnerability only affects customers who use the health monitor API.

Affected products

• Cisco Elastic Services Controller: through 5.3.0.94

References

• https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-esc-dos-4Gw6D527
• https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-esc-dos-4Gw6D527

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