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TI-2021-01039 Aliases CVE-2021-1312GHSA-3fjh-3qmq-p25v

Cisco Elastic Services Controller Denial of Service Vulnerability

Priority MEDIUM 44CWE-400Published · Updated

Key facts

Attack vector
Network
Privileges required
None
User interaction
None
Attack complexity
Low
Impact type
Denial of service
Confidentiality · integrity · availability
None · None · High
Fix status
No fix listed

Attack profile from CVSS 3.1 · NVD. Fix status from CNA. Impact type from CWE-400.

Summary

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.

Why it matters now

Exploitation None reported CISA SSVC · not in CISA KEV
EPSS 0.02555 85th percentileScored 2026-11-07
Fix No fix listed No fixed version in the sources yet

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation
None
Automatable
Yes
Technical impact
Partial

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

VendorProductAffected versionsFixed inStatusSource
CiscoCisco Elastic Services Controllerall versions—No fix listedCNA
  • Cisco Elastic Services Controller VendorCisco Affected all versions Fixed in — No fix listed CNA

CPE configurations NVD · 1

CPEVersionsRoleVendor
cpe:2.3:a:cisco:elastic_services_controller:*:*:*:*:*:*:*:*up to 5.3.0.94VulnerableCisco
  • cpe:2.3:a:cisco:elastic_services_controller:*:*:*:*:*:*:*:* Versions up to 5.3.0.94 Vulnerable ·Cisco

Remediation

No fixed version listed by the sources yet.

Timeline

  1. 2026-10-02 Threatist record created from CVE-2021-1312
  2. 2026-10-03 Alias added: GHSA-3fjh-3qmq-p25v

References

Advisory 1

  • TI-2019-01489 Cisco Elastic Services Controller REST API Authentication Bypass Vulnerability CVSS 3.0CRITICAL 10.0
  • TI-2018-00096 Improper authentication in Cisco Elastic Services Controller CVSS 3.0CRITICAL 9.8
  • TI-2017-04469 Access control flaw in Cisco Elastic Services Controller CVSS 3.0CRITICAL 9.8
  • TI-2017-04439 OS command injection in Cisco Elastic Services Controller CVSS 3.0HIGH 8.8
  • TI-2017-04468 OS command injection in Cisco Elastic Services Controller CVSS 3.0HIGH 8.8
  • TI-2017-04444 A vulnerability in Cisco Elastic Services Controllers could allow an authenticated… CVSS 3.0HIGH 8.8
See all 18 →

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences