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Critical · 9.8 CVE-2026-88351 EUVD-2026-86022GHSA-cmcq-v328-82vj

An integer overflow vulnerability exists in the MPack Node API in MPack 1.1.1 on 32-bit platforms. When parsing a specially crafted Message…

Published Sep 24, 2026 · Updated Sep 25, 2026 · Assigned by mitre

Description

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.

Fixed in Linux distributions

Distributions backport fixes, so the version that fixes this vulnerability differs per release — upgrade to at least the version shown. From the distributions' security trackers and advisories.

ReleasePackageFixed inAdvisory
Ubuntu 26.10 mpack No fix yet —

References