CVE-2026-107908: Pre-authentication heap out-of-bounds write in FalkorDB Bolt BoltReadHandler via RESET message

Severity: critical (CVSS 9.8 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.6% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2026-10-09 · updated 2026-10-15
Weakness: CWE-787

Description

A heap-based out-of-bounds write in the BoltReadHandler function (src/bolt/bolt_api.c) in FalkorDB before 4.20.0 allows a remote unauthenticated attacker to cause a denial of service and possibly execute arbitrary code by sending a Bolt RESET message with an attacker-chosen chunk size to the Bolt port. The handler checks the size only with ASSERT(), which is compiled out in release builds, then computes a destination pointer from the wire-supplied 16-bit size and moves buffered data up to about 64 KiB backwards past the start of the read buffer. Only deployments that enable the Bolt endpoint (BOLT_PORT, disabled by default) are affected.

Affected products

FalkorDB: before 4.20.0 — fixed in 4.20.0

How to fix

Upgrade to a fixed version: FalkorDB 4.20.0. Check the vendor advisory for mitigations.

References

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