CVE-2026-63140: CWE-617 Reachable Assertion in Elastic Elasticsearch
Reachable Assertion (CWE-617) in Elasticsearch can lead to denial of service via Input Data Manipulation (CAPEC-153). A specially crafted search request containing a null value in a specific query clause causes an internal assertion to be raised during query parsing. Because Elasticsearch treats assertion failures as fatal errors, this terminates the affected node process. A low-privileged authenticated user with read access to at least one index can exploit this condition with a single request to cause a node to terminate, disrupting search availability. In a single-node deployment this fully stops Elasticsearch; in a multi-node cluster it reduces cluster capacity for each affected node.
AI Analysis
Technical Summary
This vulnerability (CWE-617) in Elasticsearch allows a low-privileged authenticated user to send a specially crafted search request containing a null value in a particular query clause. This triggers an internal assertion failure during query parsing, which Elasticsearch treats as a fatal error, causing the node process to terminate. The impact is denial of service by disrupting search availability. The affected versions explicitly include 8.0.0, 9.0.0, and 9.4.0. The CVSS 3.1 base score is 6.5 (medium severity) with vector AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H, indicating network attack vector, low complexity, low privileges required, no user interaction, unchanged scope, no confidentiality or integrity impact, but high availability impact.
Potential Impact
Exploitation causes the Elasticsearch node process to terminate, resulting in denial of service. In single-node deployments, this fully stops Elasticsearch, halting all search functionality. In multi-node clusters, it reduces cluster capacity by taking nodes offline, degrading overall cluster availability. There is no impact on confidentiality or integrity according to the CVSS vector.
Mitigation Recommendations
Patch status is not yet confirmed — check the vendor advisory for current remediation guidance. No official fix or temporary workaround is currently documented. Until a fix is available, restrict read access to trusted users only to reduce risk. Monitor for unusual node terminations that may indicate exploitation attempts.
CVE-2026-63140: CWE-617 Reachable Assertion in Elastic Elasticsearch
Description
Reachable Assertion (CWE-617) in Elasticsearch can lead to denial of service via Input Data Manipulation (CAPEC-153). A specially crafted search request containing a null value in a specific query clause causes an internal assertion to be raised during query parsing. Because Elasticsearch treats assertion failures as fatal errors, this terminates the affected node process. A low-privileged authenticated user with read access to at least one index can exploit this condition with a single request to cause a node to terminate, disrupting search availability. In a single-node deployment this fully stops Elasticsearch; in a multi-node cluster it reduces cluster capacity for each affected node.
CVSS v3.1
Score 6.5medium
Affected software
pkg:maven/org.elasticsearch/elasticsearchRun on your own infrastructure? Check whether these packages are installed with threat-finder — our free open-source scanner.
Weaknesses
AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
This vulnerability (CWE-617) in Elasticsearch allows a low-privileged authenticated user to send a specially crafted search request containing a null value in a particular query clause. This triggers an internal assertion failure during query parsing, which Elasticsearch treats as a fatal error, causing the node process to terminate. The impact is denial of service by disrupting search availability. The affected versions explicitly include 8.0.0, 9.0.0, and 9.4.0. The CVSS 3.1 base score is 6.5 (medium severity) with vector AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H, indicating network attack vector, low complexity, low privileges required, no user interaction, unchanged scope, no confidentiality or integrity impact, but high availability impact.
Potential Impact
Exploitation causes the Elasticsearch node process to terminate, resulting in denial of service. In single-node deployments, this fully stops Elasticsearch, halting all search functionality. In multi-node clusters, it reduces cluster capacity by taking nodes offline, degrading overall cluster availability. There is no impact on confidentiality or integrity according to the CVSS vector.
Mitigation Recommendations
Patch status is not yet confirmed — check the vendor advisory for current remediation guidance. No official fix or temporary workaround is currently documented. Until a fix is available, restrict read access to trusted users only to reduce risk. Monitor for unusual node terminations that may indicate exploitation attempts.
Technical Details
- Data Version
- 5.2
- Assigner Short Name
- elastic
- Date Reserved
- 2026-07-15T18:23:57.166Z
- Cvss Version
- 3.1
- State
- PUBLISHED
- Remediation Level
- null
Threat ID: 6a5fdfa89c2644c7f8c1b078
Added to database: 07/21/2026, 21:07:52 UTC
Last enriched: 07/21/2026, 21:22:48 UTC
Last updated: 07/22/2026, 00:40:46 UTC
Views: 3
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