CVE-2026-63140

Reachable Assertion in Elasticsearch Leading to Denial of Service

MEDIUM
6.5
CVSS Score
Published: July 21, 2026 at 09:04 PM UTC
Updated: October 24, 2026 at 07:10 PM UTC
1 product affected across 1 vendorElasticsearch

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Severity
MEDIUM6.5
Exploit prediction
EPSS 0.4%
SSVC
No known exploit

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.

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

95%
8.0.0 ≤ v < 8.19.199.0.0 ≤ v < 9.3.89.4.0 ≤ v < 9.4.48.0.09.0.09.4.0
Affected range stops below 8.19.19, so it looks safe — our inference, not a vendor statement
Affected range stops below 9.3.8, so it looks safe — our inference, not a vendor statement
Affected range stops below 9.4.4, so it looks safe — our inference, not a vendor statement

Remediation

No guide yet

No remediation guidance has been written for this CVE yet. What the record does show:

SSVC — Action Prioritization

SSVCNo known exploitNot automatablePartial impact

SSVC signals action urgency (what to patch first), separate from CVSS which measures severity.

CVSS

6.5MEDIUMelastic
Attack Vector
NETWORK
Complexity
LOW
Privileges
LOW
User Interaction
NONE
Scope
UNCHANGED
Confidentiality
NONE
Integrity
NONE
Availability
HIGH
Vector?

Quick Info

StatusANALYZED
CWE
CWE-617

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