CVE-2026-44265 in Elo
Summary
by MITRE • 11/03/2026
Elo is a purely functional expression language for no-code tools. Prior to 1.0.1, Elo's programmatic AST API accepts arbitrary values from JSON-deserialized input, plugin output, or other untyped sources and interpolates them into generated JavaScript, Ruby, Python, or SQL without runtime syntax validation. The affected fields are int_literal / float_literal .value, variable.name, member_access.property, object_literal keys, datapath segments, lambda.params[].name, and the SQL let binding name. Crafted values become executable expressions or identifiers, allowing arbitrary code execution in JavaScript, Ruby, and Python targets and SQL injection in the SQL target. This programmatic AST-object path is distinct from the plain-string constructor-chain sandbox escape. This issue is fixed in version 1.0.1.
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Analysis
by VulDB Data Team • 11/03/2026
The Elo expression language serves as a foundational component for no-code development platforms, enabling users to define logic through declarative expressions rather than imperative code. A critical security flaw was identified within the programmatic Abstract Syntax Tree API prior to version 1.0.1 of this library. The vulnerability stems from an insufficient validation mechanism when handling data inputs that originate from JSON-deserialized payloads, plugin outputs, or other untyped sources. Unlike standard string-based parsing which may benefit from sandboxing or stricter lexical analysis, the programmatic AST construction path directly accepts arbitrary values and interpolates them into generated code targets such as JavaScript, Ruby, Python, and SQL without performing runtime syntax validation. This architectural oversight allows malicious actors to inject executable expressions or identifiers that bypass intended security boundaries.
The technical nature of this flaw is classified under CWE-74 Improper Neutralization of Special Elements in Output Used by a Downstream Component, specifically manifesting as Code Injection for scripting targets and SQL Injection for database interactions. The vulnerability affects specific fields within the AST structure, including int_literal and float_literal values, variable names, member access properties, object literal keys, datapath segments, lambda parameter names, and SQL let binding identifiers. Because these elements are directly interpolated into the final generated code without sanitization or type checking, crafted inputs can alter the semantic meaning of the expression. For instance, a value intended to be treated as a simple identifier can instead contain syntactic constructs that execute arbitrary commands when interpreted by the respective runtime environment.
The operational impact is severe due to the potential for Remote Code Execution and Data Exfiltration depending on the target language. In JavaScript, Ruby, and Python targets, an attacker who controls any of the affected AST fields can inject code snippets that are executed with the privileges of the Elo engine process. This could lead to full system compromise if the execution environment has broad file system or network access. For SQL targets, the vulnerability enables classic SQL injection attacks, allowing unauthorized data retrieval, modification, or deletion within connected databases. The distinction between this programmatic AST path and plain-string constructor-chain sandbox escapes is significant; while string-based inputs might be constrained by a specific evaluation context, the direct manipulation of AST nodes bypasses higher-level abstractions that typically enforce security policies, making exploitation more straightforward for attackers with access to these input vectors.
Mitigation strategies must prioritize immediate upgrading to version 1.0.1 or later, where this validation gap has been addressed through enhanced type checking and syntax verification during the AST construction phase. For organizations unable to upgrade immediately, defensive coding practices should be implemented by strictly validating all inputs before they are passed into Elo's programmatic API. This includes enforcing strict typing constraints on variable names and literal values, ensuring that only alphanumeric characters and safe delimiters are permitted in identifiers. Additionally, implementing a whitelist approach for allowed property keys and datapath segments can prevent the injection of malicious syntax elements. Security teams should also audit existing integrations to identify any custom plugins or data pipelines that feed untrusted JSON directly into Elo's AST constructors, as these represent high-risk attack surfaces requiring immediate remediation through input sanitization or architectural changes to decouple trusted logic from untrusted user inputs.