{"cve":"CVE-2026-54522","nvd":{"published":"2026-07-30T17:16:33.030","modified":"2026-10-23T22:10:00.160","status":"Analyzed","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_v4":{"vector":"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","score":2.1},"cvss_v3":{"version":"3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:N","score":5.4},"cwes":["CWE-416"],"references":["https://github.com/msgpack/msgpack-ruby/commit/5627d71606b565641d2dd501b82aae862f4abe90","https://github.com/msgpack/msgpack-ruby/security/advisories/GHSA-4mrv-5p47-p938","https://github.com/msgpack/msgpack-ruby/security/advisories/GHSA-4mrv-5p47-p938"],"products":["msgpack:messagepack"],"source":"nvd","synced_at":"2026-10-24T16:53:34.184483516+00:00"},"epss":{"cve":"CVE-2026-54522","score":0.00227,"percentile":0.1329,"date":"2026-10-25"},"kev":null,"osv":[{"id":"GHSA-4mrv-5p47-p938","url":"https://osv.dev/vulnerability/GHSA-4mrv-5p47-p938","summary":"MessagePack::Buffer#clear Use-After-Free that Enables Cross-Buffer Disclosure","modified":"2026-09-10T03:51:10.426858154Z","packages":[{"ecosystem":"RubyGems","name":"msgpack","purl":"pkg:gem/msgpack","ranges":["<1.8.2"],"fixed":["1.8.2"]}]}],"attribution":["This product uses the NVD API but is not endorsed or certified by the NVD.","EPSS scores: FIRST Exploit Prediction Scoring System, https://www.first.org/epss","Known exploited vulnerabilities: CISA Known Exploited Vulnerabilities Catalog, https://www.cisa.gov/known-exploited-vulnerabilities-catalog","Package advisories: OSV (https://osv.dev), from the GitHub Advisory Database, PyPA, Go, RustSec and other ecosystem databases, under CC-BY 4.0 or CC0","CVE records: the CVE Program's CVE List (https://www.cve.org), under its terms of use (https://www.cve.org/Legal/TermsOfUse). CVE is a registered trademark of The MITRE Corporation; this product is not affiliated with the CVE Program."]}