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.
Fix
Patch, vendor advisory and mitigation references on NVD 3
- https://github.com/msgpack/msgpack-ruby/commit/5627d71606b565641d2dd501b82aae862f4abe90 Patch
- https://github.com/msgpack/msgpack-ruby/security/advisories/GHSA-4mrv-5p47-p938 Exploit, Vendor Advisory
- https://github.com/msgpack/msgpack-ruby/security/advisories/GHSA-4mrv-5p47-p938 Exploit, Vendor Advisory
Every line above is quoted from NVD, CISA, Microsoft, the vendor's own advisory or DISA; nothing is generated.
Change history 1
- First seenCVSS 2.1 · msgpackNVD modified 2026-10-23 22:10
Affected (CPE criteria) 1
cpe:2.3:a:msgpack:messagepack:*:*:*:*:*:ruby:*:*
References 3
- https://github.com/msgpack/msgpack-ruby/commit/5627d71606b565641d2dd501b82aae862f4abe90 Patch
- https://github.com/msgpack/msgpack-ruby/security/advisories/GHSA-4mrv-5p47-p938 Exploit, Vendor Advisory
- https://github.com/msgpack/msgpack-ruby/security/advisories/GHSA-4mrv-5p47-p938 Exploit, Vendor Advisory