# CVE-2026-107908: FalkorDB heap-based buffer overflow in Bolt handler

Source: https://junglewise.ai/threats/cve-2026-107908-a-heap-based-out-of-bounds-write-in-the-boltreadhandler-function  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-10-09. Updated: 2026-10-16  
License: CC BY 4.0 with a link back

CVE-2026-107908 · Severity: critical · CVSS 9.8 · Published 2026-10-09

FalkorDB is a graph database that uses a network protocol called Bolt for client connections. A remote attacker can trigger a heap-based buffer overflow by sending a specially crafted Bolt message, potentially causing the database to crash or allowing arbitrary code execution. Only deployments with the optional Bolt endpoint enabled are vulnerable.

Technologies: [FalkorDB](https://junglewise.ai/threats/technologies/falkordb). Vendors: [FalkorDB](https://junglewise.ai/threats/vendors/falkordb).

## Quick answers

**Is CVE-2026-107908 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-107908 being exploited in the wild.

**How severe is CVE-2026-107908?** Critical severity, with a CVSS score of 9.8, published 9 October 2026.

**Which products and versions are affected?** FalkorDB before 4.20.0.

**Is there a fix for CVE-2026-107908?** Yes: fixed in FalkorDB 4.20.0. Until then: Disable the Bolt endpoint (BOLT_PORT configuration) if it is not required, as the Bolt protocol support is disabled by default. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

**How is CVE-2026-107908 attacked?** It is attacked over the network, in a software library.

**Am I affected by CVE-2026-107908?** Check whether you run FalkorDB at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## How to fix

- Fixed in FalkorDB 4.20.0

Disable the Bolt endpoint (BOLT_PORT configuration) if it is not required, as the Bolt protocol support is disabled by default.

## Technical details

A heap-based out-of-bounds write exists in the BoltReadHandler function (src/bolt/bolt_api.c) where the handler validates the chunk size using ASSERT() macros that are disabled in release builds. An attacker sends a Bolt RESET message with a malicious 16-bit size value, causing the handler to compute an invalid destination pointer and write up to 64 KiB of data past the buffer boundary. The vulnerability requires network access to the Bolt port and no authentication.

## Affected products

- FalkorDB FalkorDB before 4.20.0

## Timeline

- 2026-10-09: disclosed

## References

- [https://github.com/FalkorDB/FalkorDB](https://github.com/FalkorDB/FalkorDB)
- [https://github.com/FalkorDB/FalkorDB/commit/0b11a00b34b25c4d4fdfe55f0a35c8a00593bd7d](https://github.com/FalkorDB/FalkorDB/commit/0b11a00b34b25c4d4fdfe55f0a35c8a00593bd7d)

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