# CVE-2026-88409: FalkorDB buffer overflow in GraphBLAS matrix decode

Source: https://junglewise.ai/threats/cve-2026-88409-falkordb-redis-module-v4-20-1-to-v4-20-4-was-discovered-to  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-09-21. Updated: 2026-09-26  
License: CC BY 4.0 with a link back

CVE-2026-88409 · Severity: high · CVSS 8.8 · Published 2026-09-21

FalkorDB is a graph database module for Redis that stores and processes network data. Versions 4.20.1 to 4.20.4 contain a buffer overflow in the code that deserializes saved graphs, allowing an authenticated attacker or a corrupted database file to cause the database process to crash or potentially corrupt memory. The vulnerability affects both direct restore commands and automatic database loading.

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

## Quick answers

**Is CVE-2026-88409 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-88409 being exploited in the wild.

**How severe is CVE-2026-88409?** High severity, with a CVSS score of 8.8, published 21 September 2026.

**Which products and versions are affected?** FalkorDB 4.20.1 to 4.20.4.

**Is there a fix for CVE-2026-88409?** No fixed version is recorded yet. Check the vendor's advisory in the references below. If you run it, Junglewise drafts a mitigation that fits your setup and applies it once you approve, with senior security engineers behind it.

**How is CVE-2026-88409 attacked?** It is attacked over the network, in a software library.

**Am I affected by CVE-2026-88409?** 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.

## Technical details

A buffer overflow exists in _Decode_GrB_Matrix (decode_matrix.c v19) where an attacker-controlled buffer length is not validated before casting a stream buffer to a GxB_Container struct. An ineffective ASSERT check is the only validation, and it becomes a no-op in release builds. The short buffer is then passed to _decode_and_load_vector which writes live heap pointers out-of-bounds, and uninitialized struct fields are consumed by GraphBLAS library functions as trusted metadata, enabling type confusion and memory corruption.

## Affected products

- FalkorDB FalkorDB 4.20.1 to 4.20.4

## Timeline

- 2026-08-08: disclosed: Issue reported to security@falkordb.com and filed publicly on GitHub
- 2026-09-21: advisory: NVD advisory published with CVE-2026-88409

## References

- [https://github.com/FalkorDB/FalkorDB/issues/2399](https://github.com/FalkorDB/FalkorDB/issues/2399)

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