Security readout for executives and security teams
Plain-English summary
CVE-2021-1312 can let a remote unauthenticated attacker disrupt Cisco Elastic Services Controller health monitor API availability. The issue matters mainly where that API is used and reachable. It does not indicate data theft or system takeover in the provided sources.
Executive priority
Treat as a targeted availability risk for organizations relying on Cisco ESC health monitoring. Prioritize if ESC supports production network services or if the health monitor API is broadly reachable.
Technical view
The vulnerability is a resource-management flaw tied to insufficient kernel TCP connection and SYN backlog provisioning. A crafted TCP packet flood can block TCP listening ports used by the Cisco ESC health monitor API. CVSS 3.1 is 5.3, network exploitable, no privileges or user interaction required, with low availability impact only.
Likely exposure
Exposure is limited to Cisco Elastic Services Controller deployments that use the health monitor API, especially if that API is reachable from untrusted or broad networks.
Exploitation context
The source bundle does not show active exploitation, and KEV status is false. Exploitation would affect availability of health monitoring rather than confidentiality or integrity, based on the provided CVSS vector and description.
Researcher notes
Evidence is narrow and vendor-specific. The sources identify Cisco ESC and health monitor API use as the exposure condition, but do not provide version granularity in the supplied bundle. Avoid assuming impact outside ESC or beyond API availability.
Mitigation direction
- Review Cisco advisory for affected ESC releases and vendor-provided fixed release or configuration guidance.
- Limit health monitor API reachability to trusted monitoring systems and management networks.
- Disable or remove health monitor API exposure where it is not operationally required.
- Monitor ESC availability and health monitor API failures during remediation.
Validation and detection
- Inventory Cisco ESC deployments and confirm whether the health monitor API is enabled.
- Check firewall, ACL, and routing paths to identify who can reach the API.
- Review ESC monitoring logs for unexplained health monitor API availability failures.
- Validate deployed ESC versions and configuration against Cisco advisory guidance.
Public sources used
Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.
Conservative CVE-to-ATT&CK context
These mappings and lookup hints may be relevant to the vulnerability behavior, CWE, affected product, or exposure path. Glexia-inferred context is not an official MITRE, ATT&CK, CWE, or CVE Program mapping.
ATT&CK lookup starting points
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Open ATT&CK lookupCVE-2021-1312 mapping review
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Open ATT&CK lookup- Severity
- Medium
- CVSS
- 5.3 (3.1)
- Known Exploited
- No
- Published
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L
CNA and ADP enrichment extracted from CVE v5
These fields come from the CVE record and ADP containers, not from Glexia's Take. They preserve time-varying source decisions such as CISA SSVC, KEV status, CVSS metrics, and provider references.
CVSS vector scores
1 official scoreWe collect every scored CVSS vector available in the official CNA and ADP containers. When more than one version is present, the table keeps the source vectors side by side instead of collapsing them into the highest score.
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L3.91.4Primary CVE scoreVulnerability scoring details
Base CVSS 3.1 score
5.3MediumVector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L
Source materials
- CVE List V5 sourceCVE List V5
- 20210120 Cisco Elastic Services Controller Denial of Service VulnerabilityCVE reference · vendor-advisory, x_refsource_CISCO
Products and packages named in the record
CWE details
CWE links open Glexia weakness intelligence pages with official CWE context, developer remediation guidance, and related CVE mappings.
Uncontrolled Resource Consumption
Uncontrolled Resource Consumption represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.