Apache DataSketches: datasketches-cpp: Out-of-bounds read in compact Theta sketch deserialization allows denial of service via a crafted sketch

{
  "id": "caeb24c4d723173ef3da05cd3ae8100f696756231256ebb7e8cac64975487767",
  "url": "https://osv.dev/vulnerability/CVE-2026-103635",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "Apache DataSketches: datasketches-cpp: Out-of-bounds read in compact Theta sketch deserialization allows denial of service via a crafted sketch",
    "summary": "Out-of-bounds read in the compact Theta sketch deserialization of Apache DataSketches C++ (repo: datasketches-cpp). compact_theta_sketch::deserialize() and wrapped_compact_theta_sketch::wrap() read header fields before checking that the input was long enough. For the compressed format, the size check could be defeated by a 32-bit overflow, and two header fields that control decoding were not validated; this also affected deserialization from a stream. A crafted or truncated sketch could cause a read past the end of the input. In the compressed case the over-read can be large, and the bytes read can become part of the deserialized sketch. This can cause a crash (denial of service) and could expose adjacent memory contents. This issue affects Apache DataSketches C++: from 3.1.0 before 5.3.0. Only applications that deserialize Theta sketches from untrusted sources are affected. Users are recommended to upgrade to version 5.3.0, which fixes this issue.",
    "evidence": "osv:CVE-2026-103635",
    "products": [],
    "severity": "critical",
    "structured": {
      "id": "CVE-2026-103635",
      "aliases": [
        "CVE-2026-103635"
      ],
      "metrics": [
        {
          "type": "CVSS_V3",
          "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:H"
        }
      ],
      "affected": [
        {
          "ranges": [
            {
              "repo": "https://github.com/apache/datasketches-cpp",
              "type": "GIT",
              "events": [
                {
                  "introduced": "a375f9805ab8064b20e6a1b82282e4d04b102328"
                },
                {
                  "fixed": "5b5524f55d121225a7909c2851271327684585d7"
                }
              ],
              "database_specific": {
                "extracted_events": [
                  {
                    "range": [
                      {
                        "introduced": "3.1.0"
                      },
                      {
                        "last_affected": "5.2.0"
                      }
                    ],
                    "source": "AFFECTED_FIELD",
                    "strategy": "StandardRange"
                  },
                  {
                    "range": [
                      {
                        "fixed": "5b5524f55d121225a7909c2851271327684585d7"
                      }
                    ],
                    "source": "REFERENCES_TAG",
                    "original_tag": "5.3.0"
                  }
                ]
              }
            }
          ],
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-103635.json"
          }
        }
      ],
      "modified": "2026-10-28T02:30:31.293648243Z",
      "provider": "osv",
      "references": [
        "https://github.com",
        "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/103xxx/CVE-2026-103635.json",
        "https://github.com/apache/datasketches-cpp/releases/tag/5.3.0",
        "https://lists.apache.org/thread/15b86y9jstco39kzppjw7l5kvhjvwqvv",
        "https://nvd.nist.gov/vuln/detail/CVE-2026-103635"
      ],
      "provider_metadata": {
        "cwe_ids": [
          "CWE-125",
          "CWE-190"
        ],
        "cna_assigner": "apache",
        "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/103xxx/CVE-2026-103635.json"
      }
    },
    "related_cves": [
      {
        "value": "CVE-2026-103635",
        "evidence": "/id"
      }
    ],
    "security_relevant": true,
    "severity_evidence": "/severity/0/score"
  },
  "source_id": "core-osv",
  "document_id": 498323,
  "published_at": "2026-10-10T10:23:48.598+00:00"
}