CVE-2026-54522 affecting package python-msgpack 1.0.5-3

{
  "id": "0cc08528499866a146975555ce499db7fb4d21f98b93d9baac66b428e0e19aa9",
  "url": "https://osv.dev/vulnerability/AZL-109539",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "CVE-2026-54522 affecting package python-msgpack 1.0.5-3",
    "summary": "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.",
    "evidence": "osv:AZL-109539",
    "products": [
      {
        "name": {
          "value": "python-msgpack",
          "evidence": "/affected/0/package/name"
        },
        "prerequisites": [],
        "fixed_versions": [],
        "affected_versions": []
      }
    ],
    "severity": "unknown",
    "structured": {
      "id": "AZL-109539",
      "aliases": [
        "AZL-109539"
      ],
      "affected": [
        {
          "ranges": [
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "0"
                },
                {
                  "last_affected": "1.0.5-3"
                }
              ]
            }
          ],
          "package": {
            "name": "python-msgpack",
            "purl": "pkg:rpm/azure-linux/python-msgpack",
            "ecosystem": "Azure Linux:3"
          },
          "database_specific": {
            "source": "https://github.com/microsoft/AzureLinuxVulnerabilityData/blob/main/osv/AZL-109539.json"
          }
        }
      ],
      "modified": "2026-10-27T05:36:16Z",
      "provider": "osv",
      "upstream": [
        "CVE-2026-54522"
      ],
      "references": [
        "https://nvd.nist.gov/vuln/detail/CVE-2026-54522"
      ]
    },
    "related_cves": [
      {
        "value": "CVE-2026-54522",
        "evidence": "/upstream"
      }
    ],
    "security_relevant": true,
    "severity_evidence": null
  },
  "source_id": "core-osv",
  "document_id": 460478,
  "published_at": "2026-07-30T17:16:33+00:00"
}