Junglewise Threat Intelligence

CVE-2026-63136: Elastic Elasticsearch denial of service via excessive memory allocation

CVE-2026-63136 · Severity: medium · CVSS 6.5 · Published 2026-07-21

Technologies: Elasticsearch. Vendors: Elastic.

Executive brief

Elasticsearch, a widely used search and analytics engine, is vulnerable to a denial-of-service attack. An authenticated user with search permissions can send a specially crafted request that exhausts the system's memory. This can lead to service outages, cluster instability, and may require manual intervention to restore normal operations.

Technical details

A vulnerability classified as Uncontrolled Resource Consumption (CWE-400) exists in Elasticsearch. The flaw is triggered when a user with search privileges submits a specially crafted search request that causes a data node to exhaust its available heap memory (CAPEC-130). This is a network-based attack that requires low privileges (authenticated search access) but no user interaction. The resulting memory exhaustion leads to node unavailability and potential cluster-wide degradation. The issue is resolved in Elasticsearch versions 8.19.15, 9.2.9, and 9.3.4. The 9.4.x release line is not affected.

Affected products

  • Elastic Elasticsearch 8.0.0 to 8.19.14, 9.0.0 to 9.2.8, 9.3.0 to 9.3.3

Timeline

  • 2026-07-21: advisory: Public disclosure by Elastic and NVD publication
  • 2026-07-21: patched: Fixes released in versions 8.19.15, 9.2.9, and 9.3.4

References

Related threats