CVE-2026-88410 Overview
CVE-2026-88410 affects FalkorDB, a graph database implemented as a Redis module. The graph.UDF command in versions v4.20.1 through v4.20.4 is not registered as a write command. This misclassification causes the Redis module to treat state-modifying operations as read-only. Authenticated attackers with low privileges can leverage this flaw over the network to trigger unexpected application behavior and impact availability. The issue is tracked under [CWE-306: Missing Authentication for Critical Function] and stems from an incorrect command flag rather than a memory safety error.
Critical Impact
Authenticated network attackers can invoke graph.UDF against replica or read-only contexts, producing state inconsistency and high availability impact on affected FalkorDB deployments.
Affected Products
- FalkorDB Redis module v4.20.1
- FalkorDB Redis module v4.20.2, v4.20.3
- FalkorDB Redis module v4.20.4
Discovery Timeline
- 2026-09-21 - CVE-2026-88410 published to NVD
- 2026-09-24 - Last updated in NVD database
Technical Details for CVE-2026-88410
Vulnerability Analysis
FalkorDB extends Redis with graph query capabilities exposed through commands such as graph.QUERY and graph.UDF. Redis requires modules to declare each command's semantics using flags including write, readonly, and denyoom. These flags govern replication behavior, replica read handling, cluster routing, and ACL enforcement.
The graph.UDF command in FalkorDB v4.20.1 through v4.20.4 is registered without the write flag despite performing state-changing operations. Redis therefore routes the command as if it were safe against read-only contexts. This routing mismatch produces inconsistent state between primary and replica nodes and can break replication invariants.
The vulnerability requires network access and a low-privileged authenticated Redis client. It does not require user interaction. The confidentiality impact is none, integrity impact is low, and availability impact is high because inconsistent replicas can trigger service disruption.
Root Cause
The root cause is an incorrect Redis command registration flag. graph.UDF mutates database state but was declared without the write attribute, so Redis does not enforce write-command semantics on it. This is a classic case of missing authorization for a critical function [CWE-306], where an access-control decision is delegated to command metadata that misrepresents the operation.
Attack Vector
An attacker authenticates to a FalkorDB instance with any account permitted to execute graph.UDF. The attacker then issues graph.UDF against a replica or in a context where write commands should be rejected. Because Redis does not classify the command as a write, it accepts and executes the request, mutating state that should have remained immutable. See the GitHub Issue Discussion for maintainer analysis.
No verified public exploit code exists for this vulnerability. Refer to the upstream issue tracker for reproduction details.
Detection Methods for CVE-2026-88410
Indicators of Compromise
- Unexpected divergence between FalkorDB primary and replica graph state following graph.UDF invocations.
- Replica nodes accepting graph.UDF commands from clients despite being configured as read-only.
- Replication errors, resync events, or replica disconnects correlated with graph.UDF traffic.
Detection Strategies
- Enable Redis command logging or MONITOR sampling to identify clients invoking graph.UDF on replica endpoints.
- Correlate FalkorDB version banners (v4.20.1–v4.20.4) with exposed Redis ports discovered via internal asset inventory.
- Compare graph checksums or query result sets between primary and replicas to detect state drift.
Monitoring Recommendations
- Alert on any graph.UDF execution originating from non-administrative service accounts.
- Monitor Redis INFO replication output for unexpected master_link_status changes on FalkorDB nodes.
- Ingest Redis slowlog and ACL logs into a centralized SIEM for retention and correlation.
How to Mitigate CVE-2026-88410
Immediate Actions Required
- Inventory all FalkorDB instances and identify hosts running v4.20.1 through v4.20.4.
- Restrict network exposure of FalkorDB Redis ports to trusted application subnets only.
- Revoke or scope down ACL permissions so only administrative users can execute graph.UDF.
Patch Information
Refer to the FalkorDB GitHub issue for maintainer guidance and upgrade instructions. Upgrade to a FalkorDB release that registers graph.UDF with the correct write command flag once available from the vendor.
Workarounds
- Use Redis ACLs to block graph.UDF for non-admin users until a patched release is deployed.
- Terminate client traffic to replicas at the proxy layer and route only reads that exclude graph.UDF.
- Enforce mutual TLS and strong authentication on all FalkorDB endpoints to reduce the attacker population.
# Example Redis ACL to deny graph.UDF for the application role
ACL SETUSER app_reader on >STRONG_PASSWORD ~* +@read -graph.UDF
ACL SETUSER app_writer on >STRONG_PASSWORD ~* +@all -graph.UDF
# Only grant graph.UDF to a dedicated admin identity
ACL SETUSER graph_admin on >ADMIN_PASSWORD ~* +@all +graph.UDF
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
