Description

Improper error handling in the GRAPH.EFFECT component (/effects/effects_apply.c) of FalkorDB (Redis module) v4.20.1 leads to a Denial of Service (DoS) within the application.

Executive Summary

Technical Details

Mitigations

References

Additional Metadata

{
  "score": "7.5",
  "pubDate": "2026-09-21T21:17:15.380Z",
  "pubdate": "2026-09-21T21:17:15.380Z",
  "executiveSummary": "A Denial of Service (DoS) vulnerability exists within the GRAPH.EFFECT component of FalkorDB version 4.20.1, stemming from improper error handling in the /effects/effects_apply.c file.\nThe vulnerability allows an attacker to trigger an application-level crash, resulting in the unavailability of the Redis module and potentially impacting the entire Redis instance depending on the configuration.\nThis issue is classified as a resource management or error-handling flaw that compromises system stability.\nThe vulnerability does not necessarily require advanced administrative privileges for execution if the Redis instance allows the invocation of the GRAPH.EFFECT command.\nRisk implications include service disruption, loss of data availability, and potential cascading failure of dependent systems relying on the database module.\nExploitation requires an attacker to submit specifically crafted or erroneous input to the affected module to trigger the unhandled exception or critical logic error.",
  "technicalDetails": "The vulnerability is located in the GRAPH.EFFECT component, specifically within the source code file /effects/effects_apply.c. The root cause is identified as improper error handling during the execution of effect application logic.\nIn FalkorDB v4.20.1, the /effects/effects_apply.c component is responsible for processing side effects associated with graph operations. When the component encounters a specific, malformed, or unexpected state during this processing, the current implementation fails to gracefully catch or recover from the error state.\nThe failure to properly validate inputs or manage execution states leads to an unhandled exception or an inconsistent internal memory state, causing the Redis module—and by extension, the Redis process—to terminate abruptly.\nAttack Flow: 1. An attacker gains access to the Redis interface where the FalkorDB module is loaded. 2. The attacker crafts a request invoking the GRAPH.EFFECT function with parameters designed to trigger the identified error path in /effects/effects_apply.c. 3. Upon processing the malicious input, the code enters an error-handling branch that is insufficiently robust or improperly implemented, resulting in a segmentation fault or a process abort signal.\nThe impact is a complete Denial of Service (DoS) for the database service. Because Redis processes are typically single-threaded, a crash within a loaded module effectively halts all database operations and incoming connections. If the Redis server is configured to restart automatically, this vulnerability can be leveraged to cause continuous service cycles, preventing legitimate users from accessing or writing data.\nThe vulnerability does not require complex remote code execution (RCE) chains; it is a direct exploitation of logic errors that compromise the stability of the daemon. No specific network exposure beyond access to the Redis port is required for an attacker to initiate this crash. The vulnerability is intrinsic to the interaction between the user-supplied data and the internal state management logic within the /effects/effects_apply.c function."
}