Quick answers
- Is CVE-2026-107909 exploited in the wild?
- No. Junglewise Threat Intelligence has no report of CVE-2026-107909 being exploited in the wild.
- How severe is CVE-2026-107909?
- Critical severity, with a CVSS score of 9.1, published 9 October 2026.
- Which products and versions are affected?
- FalkorDB before 4.20.0.
- Is there a fix for CVE-2026-107909?
- Yes: fixed in FalkorDB 4.20.0. Until then: Disable the Bolt endpoint (BOLT_PORT setting) unless explicitly required, as it is disabled by default in production deployments. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.
- How is CVE-2026-107909 attacked?
- It is attacked over the network, in a hosted service.
- Am I affected by CVE-2026-107909?
- 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 setting) unless explicitly required, as it is disabled by default in production deployments.
Technical details
A heap-based out-of-bounds write exists in the ws_read_frame function (src/bolt/ws.c) and buffer_apply_mask function (src/bolt/buffer.c) when handling WebSocket frames with 64-bit extended payload lengths. The payload length is not properly validated, and the only bounds check in buffer_apply_mask is an ASSERT() macro that is compiled out in release builds. An unauthenticated attacker on the network can send a crafted frame that causes the mask-application function to XOR memory beyond the receive buffer with an attacker-supplied mask key, leading to denial of service and potential heap corruption.
Affected products
- FalkorDB FalkorDB before 4.20.0
Timeline
- 2026-10-09: disclosed