CVE-2026-54522
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 4.0
- 2.1
CVSS:4.0/AV:L/AC:L/AT:P/PR:N/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N - CVSS 3.1
- 5.4
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:N - EPSS
- 0.2% chance of exploitation in the next 30 days; higher than 13% of CVEs (scores of 2026-10-25)
- CWE
- CWE-416
- Published
- Modified
- Record from
- the NVD, synced
Affected
- msgpack:messagepack
Packages (OSV)
| Advisory | Ecosystem | Package | Affected | Fixed in |
|---|---|---|---|---|
| GHSA-4mrv-5p47-p938 | RubyGems | msgpack | <1.8.2 | 1.8.2 |