Vulnerability Description
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.
CVSS Score
MEDIUM
Affected Products
| Vendor | Product | Versions |
|---|---|---|
| Msgpack | Messagepack | < 1.8.2 |
Related Weaknesses (CWE)
References
- https://github.com/msgpack/msgpack-ruby/commit/5627d71606b565641d2dd501b82aae862Patch
- https://github.com/msgpack/msgpack-ruby/security/advisories/GHSA-4mrv-5p47-p938ExploitVendor Advisory
- https://github.com/msgpack/msgpack-ruby/security/advisories/GHSA-4mrv-5p47-p938ExploitVendor Advisory
FAQ
What is CVE-2026-54522?
CVE-2026-54522 is a vulnerability with a CVSS score of 5.4 (MEDIUM). 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 s...
How severe is CVE-2026-54522?
CVE-2026-54522 has been rated MEDIUM with a CVSS base score of 5.4/10. Review the CVSS metrics above for detailed severity breakdown.
Is there a patch for CVE-2026-54522?
Check the references section above for vendor advisories and patch information. Affected products include: Msgpack Messagepack.