Vulnerability · Published Oct 9, 2026 · Assigned by securin
CVE-2026-107909Pre-authentication heap out-of-bounds write in FalkorDB Bolt WebSocket frame handling via unbounded payload length
Critical 9.1
In plain English
A critical-severity out-of-bounds write in FalkorDB from FalkorDB. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.4% (higher than 38% of all known vulnerabilities).
Official description
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 (as reported)
Weakness: CWE-787 · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:H
References
- FalkorDB PR #2170 patch
- Fix commit patch
- FalkorDB 4.20.0 release notes release-notes