CVE-2026-54522 — MessagePack::Buffer#clear Use-After-Free that Enables Cross-Buffer Disclosure
MessagePack for Ruby is an implementation of the MessagePack binary serialization format. Prior to 1.8.2, MessagePack::Buffer#clear in ext/msgpack/buffer.c leaves rmem_last, rme…
Published: 2026-07-30 · CVSS: 2.1 · CVSS 4.0
MessagePack for Ruby is an implementation of the MessagePack binary serialization format. Prior to 1.8.2, MessagePack::Buffer#clear in ext/msgpack/buffer.c leaves rmem_last, rmem_end, and rmem_owner stale after _msgpack_buffer_shift_chunk returns an rmem page to the shared pool, allowing a subsequent Buffer#write and a second MessagePack::Buffer to alias the page and disclose or corrupt cross-buffer data. This issue is fixed in version 1.8.2.
Source: CVE Program · Revision 8b16575c39f1e1810c5e863010da073d2d3285e7