CVE-2026-88351
An integer overflow vulnerability exists in the MPack Node API in MPack 1.1.1 on 32-bit platforms. When parsing a specially crafted MessagePack array32 or map32 object with an excessively large element count, the page allocation size calculation in mpack_tree_parse_children() can overflow size_t and produce an undersized allocation. Subsequent parsing writes mpack_node_data_t records beyond the allocated heap buffer, resulting in heap-buffer-overflow, memory corruption, and denial of service.
- Published Sep 24, 2026
- CVSS 9.8 critical
- 0.3% chance of exploitation in the next 30 days (EPSS)
- A fix is available