CVE-2026-103008 in Elasticsearch
Summary
by MITRE • 10/06/2026
Uncontrolled Recursion (CWE-674) in Elasticsearch can lead to Denial of Service via a specially crafted request that causes the server to construct and process a deeply nested data structure with no bound on recursion depth. Elasticsearch contains an uncontrolled recursion weakness in how it builds and serializes geometry values produced by scripted runtime fields. Unlike geometry supplied as text, which is subject to a nesting-depth limit, geometry constructed from a script's output is not bounded. An authenticated user with read access to a single index can submit a request defining such a field with a script that produces a deeply nested structure. Processing this request recurses past the available stack space, causing the affected node to terminate. The node does not recover automatically on all deployments and may require manual intervention to restore service.
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Analysis
by VulDB Data Team • 10/07/2026
The vulnerability identified as CVE-2024-xxxx represents an Uncontrolled Recursion flaw within Elasticsearch, formally classified under CWE-674. This security weakness arises from a fundamental inconsistency in how the application handles geometry data structures depending on their origin. Specifically, while standard text-based geometry inputs are subjected to strict nesting-depth limits to prevent stack exhaustion, geometry values generated dynamically through scripted runtime fields bypass these protective boundaries. The core technical flaw lies in the serialization and processing logic for script-generated geometric objects, which fails to enforce a maximum recursion depth during construction. This oversight allows an attacker to craft requests that trigger infinite or excessively deep recursive calls within the server's execution stack.
From an operational perspective, this vulnerability enables a Denial of Service attack against Elasticsearch clusters. An authenticated user possessing read access to at least one index can exploit this flaw by submitting a specially crafted request that defines a runtime field with a script designed to produce deeply nested geometric structures. When the server attempts to process and serialize these unbounded recursive data structures, it rapidly consumes available stack space. This resource exhaustion causes the affected Elasticsearch node to crash or terminate unexpectedly. The impact is severe because the service disruption is not always self-healing; in many deployment configurations, the crashed node does not automatically recover, requiring manual intervention by system administrators to restart services and restore cluster stability.
This vulnerability aligns with ATT&CK technique T1499, Endpoint Denial of Service, as it involves manipulating software behavior to exhaust computational resources such as CPU or memory stack space. The lack of input validation for recursive depth in script-generated outputs highlights a critical gap in the application's defensive coding practices. To mitigate this risk, organizations should immediately apply vendor-provided patches that enforce consistent recursion limits across all geometry processing pathways, regardless of whether the data originates from static text fields or dynamic scripts. Additionally, administrators should review access controls to ensure that only trusted users have permission to define runtime fields with custom scripting capabilities, thereby reducing the attack surface for potential exploitation by malicious insiders or compromised accounts.