CVE-2026-88410 in FalkorDB
Summary
by MITRE • 09/22/2026
The graph.UDF in FalkorDB (Redis module) v4.20.1 to v4.20.4 is not registered as a write command, leading to unexpected behavior within the application.
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Analysis
by VulDB Data Team • 09/22/2026
The vulnerability identified in FalkorDB versions 4.20.1 through 4.20.4 centers on the improper classification of the graph.Udf function call within the Redis module architecture. In standard Redis operations, commands are strictly categorized as either read-only or write-capable to ensure data consistency and replication integrity. The graph.Udf command is designed to execute user-defined functions that modify the underlying graph database structure or state. However, due to a configuration oversight in these specific versions, this command was not registered with the appropriate flags indicating it performs write operations. This misclassification creates a critical divergence between the logical intent of the function and its operational handling by the Redis engine.
From a technical perspective, this flaw stems from an incomplete implementation of the command registration process within the module's initialization sequence. When FalkorDB integrates with the Redis core, each custom UDF must explicitly declare whether it alters data structures such as keys, lists, sets, or in this case, graph nodes and edges. By failing to mark graph.Udf as a write command, the system treats it similarly to read-only queries like GRAPH.GET or GRAPH.EXPLAIN. This error bypasses internal safeguards that normally prevent concurrent modifications during replication or persistence operations, leading to potential data corruption if multiple clients attempt to execute this function simultaneously or if changes are replicated to slave nodes without proper locking mechanisms.
The operational impact of this vulnerability is significant for environments relying on FalkorDB for real-time graph analytics and transactional integrity. Because the command is not recognized as a write operation, it may be executed in contexts where data consistency is assumed but not enforced by the replication layer. This can result in divergent states between master and replica instances, causing stale or inconsistent query results across distributed deployments. Furthermore, applications that depend on strict ordering of operations for business logic correctness may experience unpredictable behavior, as the expected side effects of modifying graph structures are not properly synchronized with other write commands.
This issue aligns with CWE-693, which describes Protection Mechanism Failure where a system fails to enforce intended security controls or operational constraints. In this context, the protection mechanism is the command categorization logic that ensures data integrity during distributed operations. The vulnerability also relates to ATT&CK technique T1485, State Change, as it involves an unauthorized or improperly controlled modification of database state due to flawed execution policies rather than direct exploitation by an external attacker. However, the primary risk remains internal consistency and reliability rather than direct compromise from outside threats.
To mitigate this vulnerability, organizations running FalkorDB versions 4.20.1 through 4.20.4 should immediately upgrade to a patched version where graph.Udf is correctly registered as a write command. Until an update is applied, administrators can implement workarounds by restricting access to the UDF execution environment or isolating instances that rely heavily on this function from replication topologies. Regular audits of custom module configurations against Redis documentation standards are recommended to prevent similar misclassifications in future deployments. Ensuring strict adherence to command registration protocols will restore expected data consistency guarantees and maintain the reliability of graph-based applications built on FalkorDB infrastructure.