External risk intelligence

FalkorDB Stack Overflow Denial of Service Vulnerability

CVE advisorySeverity: CRITICAL (CVSS 9.2)

CVE-2026-7827

FalkorDB is a graph database typically deployed as a backend component within internal service architectures. While it uses network protocols, exposing raw database replication or command interfaces directly to the public internet is not a standard or recommended deployment practice, usually occurring only due to misconfiguration rather than intended public-facing functionality.

Buffer Overflow

Halo Surface Signal: 2 out of 5 — less likely to be public-facing.

External exposure likelihood

Horizon Alert

Summary of the vulnerability and why it matters

A critical vulnerability has been identified in FalkorDB's graph decoders that could allow an attacker to disrupt services or potentially execute code. This stems from a buffer overflow issue in how certain data is processed, which could be triggered by specially crafted inputs. The main concern is to confirm if this technology is in use and whether it is exposed in a way that could be targeted.

Flaw allows code execution via crafted data.
Confirms if FalkorDB is in use and exposed.
Assess relevance and potential exposure.

Attack Path

How an attacker could exploit the issue

An attacker could target a FalkorDB instance by exploiting a vulnerability in its RDB graph decoders. If an attacker can issue Redis replication commands to an instance, such as one without a password, they may be able to send a specially crafted RDB stream. This stream could contain an entity property count that causes a stack-based buffer overflow in the `_RdbLoadEntity` function, potentially leading to denial of service or arbitrary code execution.

Remote attackers can trigger vulnerability.
Malformed RDB stream in replication.
Denial of service or code execution.

Live Threat

Current exploitation, exposure, and threat context

A remote attacker who can issue Redis replication commands could cause a denial of service or potentially execute arbitrary code by providing a crafted RDB stream. This could affect the availability and integrity of the FalkorDB service when specific conditions, such as unauthenticated replication, are met.

FalkorDB service availability and integrity.
Unauthenticated replication allows crafted RDB stream.
Service disruption or potential code execution.

Operational Fix

Recommended remediation, mitigation, and detection steps

Application owners and infrastructure teams are likely responsible for addressing this vulnerability in FalkorDB. The first practical step is to identify all FalkorDB instances, determine their reachability and business criticality, and locate the accountable owner to plan remediation.

Confirm FalkorDB deployment and exposure.
Identify accountable application owners.
Plan risk-based remediation.

Supplementary metadata

CVSS vector

Validate whether this threat affects your internet-facing exposure.

Halo Threat Intelligence helps prioritize remediation with Halo Surface Signal and H/A/L/O context. Start exposure validation with a free external attack surface trial.

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Frequently asked questions

What is FalkorDB?

FalkorDB is a high-performance graph database designed to manage complex, interconnected data relationships. It is frequently utilized by developers as a backend engine for applications requiring rapid graph traversals and analysis. The software often integrates with existing Redis-compatible ecosystems to provide these specialized data handling capabilities within larger service architectures.

What does CVE-2026-7827 mean by a stack-based buffer overflow?

This vulnerability, classified as CWE-121, occurs when a program writes more data to a memory area on the execution stack than it can hold. In FalkorDB, the RDB graph decoder fails to set an upper limit on property counts within incoming data streams. Because the software allocates memory for these inputs directly on the thread stack, a specially crafted stream forces the application to overwrite adjacent memory, leading to crashes or potential unauthorized code execution.

How can an attacker trigger this FalkorDB vulnerability?

An attacker triggers the bug by sending a maliciously crafted RDB stream to an instance that accepts Redis replication commands. The exploit relies on the database's willingness to process this stream without validation. Notably, simply sending standard database queries will not trigger this flaw; the attacker must be able to interact with the specific replication interface, which is often left accessible if instances lack password authentication.

Do I need to worry if my FalkorDB instance is internal?

Halo Surface Signal indicates that FalkorDB is typically used as a backend component for internal services. If your instance is not exposed to the public internet and is restricted to trusted internal networks, the likelihood of a remote attacker reaching the replication interface is significantly lower. The highest risk exists for instances misconfigured to allow unauthorized network access to their command or replication ports.

How should I respond to CVE-2026-7827?

The most effective first step is to perform an inventory of your environment to identify all active FalkorDB instances. Once located, verify their network reachability and confirm that strong authentication is enabled for all interfaces, especially replication. Finally, coordinate with your infrastructure teams to assess these instances and plan for an update to version 4.18.4 or later, which contains the necessary security hardening for the decoder.

References

Written by Nicholas Merritt

Nicholas Merritt is VP of Security Solutions at Halo Security. With more than 25 years across application security, vulnerability prioritization, and offensive security, he helps teams translate threat data into practical exposure validation and remediation focus. He authors Halo Threat Intelligence CVE advisories using Halo Surface Signal and H/A/L/O context to prioritize internet-facing risk.