CVE-2026-116733: flatcc through 0.6.4 Out-of-Bounds Read via __flatcc_json_parser_number
flatcc through 0.6.4 contains an out-of-bounds read vulnerability in flatccjsonparsernumber that allows attackers to read past the input buffer via numbers ending in a decimal point. Attackers can supply untrusted JSON ending immediately after a decimal point to generated parsers, crashing applications when the buffer ends at an unmapped page.
Affected Software
Event History
Frequently Asked Questions
Which deployments are exposed to this issue?
Applications using Dvidelabs flatcc through version 0.6.4 are exposed when they pass attacker-controlled JSON to generated parsers. The practical impact is a crash when a malformed numeric value ends with a decimal point exactly at an unmapped page boundary.
What input is needed to trigger the out-of-bounds read?
An attacker must be able to supply untrusted JSON containing a number that ends in a decimal point, with the input ending immediately after that point. Exploitation requires the buffer layout to place that end at an unmapped page, making the read cause a crash.
What is the security impact?
The reported impact is denial of service through an application crash. The supplied severity vector indicates no confidentiality or integrity impact, no privileges or user interaction required, and high attack complexity.