medium5.4
CVE-2026-54522
MessagePack for Ruby is an implementation of the MessagePack binary serialization format.
Impact
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.
Affected packages
| Ecosystem | Package | Affected | Fixed in |
|---|---|---|---|
| rubygems | msgpack | <= 1.8.1 | 1.8.2 |
Affected products
| Vendor | Product | Affected versions |
|---|---|---|
| Msgpack | Messagepack | before 1.8.2 |
Weakness classification
References
- NVD record
- CVE.org record
- GitHub advisory
- https://github.com/advisories/GHSA-4mrv-5p47-p938
- https://github.com/msgpack/msgpack-ruby/security/advisories/GHSA-4mrv-5p47-p938
- https://github.com/msgpack/msgpack-ruby/commit/5627d71606b565641d2dd501b82aae862f4abe90
- https://github.com/rubysec/ruby-advisory-db/blob/master/gems/msgpack/CVE-2026-54522.yml
- https://www.cve.org/CVERecord/SearchResults?query=CVE-2026-54522