CVE-2026-107909: Falkordb

Critical severity, CVSS 9.1. EPSS: 0.4% chance of exploitation in the next 30 days.

A heap-based out-of-bounds write in the ws_read_frame function (src/bolt/ws.c) and the buffer_apply_mask function (src/bolt/buffer.c) in FalkorDB before 4.20.0 allows a remote unauthenticated attacker to cause a denial of service and possibly corrupt heap memory by sending a WebSocket frame with a 64-bit extended payload length to the Bolt port. The payload length is not bounded, and the only bounds check in buffer_apply_mask is an ASSERT(), which is compiled out in release builds, so the function XORs memory beyond the end of the receive buffer with the attacker-supplied mask key. Only deployments that enable the Bolt endpoint (BOLT_PORT, disabled by default) are affected.

Affected products

• Falkordb Falkordb: before 4.20.0 (fixed in 4.20.0)

Published 2026-10-09. Last modified 2026-10-09.