{
  "affected": [
    {
      "ranges": [
        {
          "database_specific": {
            "cpe": "cpe:2.3:a:msgpack:messagepack:*:*:*:*:*:ruby:*:*",
            "extracted_events": [
              {
                "introduced": "0"
              },
              {
                "fixed": "1.8.2"
              }
            ],
            "source": [
              "CPE_RANGE",
              "REFERENCES"
            ]
          },
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "09c914d75f296d6edb9fadb65b9ad614eb0bbfc7"
            },
            {
              "fixed": "5627d71606b565641d2dd501b82aae862f4abe90"
            }
          ],
          "repo": "https://github.com/msgpack/msgpack-ruby",
          "type": "GIT"
        }
      ]
    }
  ],
  "aliases": [
    "GHSA-4mrv-5p47-p938"
  ],
  "database_specific": {
    "cna_assigner": "GitHub_M",
    "cwe_ids": [
      "CWE-416"
    ],
    "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/54xxx/CVE-2026-54522.json"
  },
  "details": "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.",
  "id": "CVE-2026-54522",
  "modified": "2026-08-12T03:51:31.635429792Z",
  "published": "2026-07-30T16:33:06.080Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/54xxx/CVE-2026-54522.json"
    },
    {
      "type": "ADVISORY",
      "url": "https://github.com/msgpack/msgpack-ruby/security/advisories/GHSA-4mrv-5p47-p938"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-54522"
    },
    {
      "type": "FIX",
      "url": "https://github.com/msgpack/msgpack-ruby/commit/5627d71606b565641d2dd501b82aae862f4abe90"
    }
  ],
  "schema_version": "1.9.0",
  "severity": [
    {
      "score": "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",
      "type": "CVSS_V4"
    }
  ],
  "summary": "MessagePack::Buffer#clear Use-After-Free that Enables Cross-Buffer Disclosure"
}