MinIO affected a DoS via Unbounded Memory Allocation in S3 Select CSV Parsing

{
  "id": "376097add91c92d56c1435c4eb5528bb45e0c727dd78a0b9b42d15c21531507c",
  "url": "https://osv.dev/vulnerability/GHSA-h749-fxx7-pwpg",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "MinIO affected a DoS via Unbounded Memory Allocation in S3 Select CSV Parsing",
    "summary": "### Impact _What kind of vulnerability is it? Who is impacted?_ MinIO's S3 Select feature is vulnerable to memory exhaustion when processing CSV files containing lines longer than available memory. The CSV reader's `nextSplit()` function calls `bufio.Reader.ReadBytes('\\n')` with no size limit, buffering the entire input in memory until a newline is found. A CSV file with no newline characters causes the entire contents to be read into a single allocation, leading to an OOM crash of the MinIO server process. This is exploitable by any authenticated user with `s3:PutObject` and `s3:GetObject` permissions. The attack is especially practical when combined with compression: a ~2 MB gzip-compressed CSV can decompress to gigabytes of data without newlines, allowing a small upload to cause large memory consumption on the server. However, compression is not required — a sufficiently large uncompressed CSV with no newlines triggers the same issue. **Affected component:** `internal/s3select/csv/reader.go`, function `nextSplit()`. **CWE:** CWE-770 (Allocation of Resources Without Limits or Throttling) ### Affected Versions All MinIO releases are through the final release of the minio/minio open-source project. The vulnerability was introduced in commit https://github.com/minio/minio/commit/7c14cdb60e53dbfdad2be644dfb180cab19fffa7, which added S3 Select support for CSV. The CSV reader has used unbounded line reads since this commit (originally via Go's stdlib `encoding/csv.Reader`, later ",
    "evidence": "osv:GHSA-h749-fxx7-pwpg",
    "products": [
      {
        "name": {
          "value": "github.com/minio/minio",
          "evidence": "/affected/0/package/name"
        },
        "prerequisites": [],
        "fixed_versions": [],
        "affected_versions": []
      }
    ],
    "severity": "high",
    "structured": {
      "id": "GHSA-h749-fxx7-pwpg",
      "aliases": [
        "CVE-2026-39414",
        "GHSA-h749-fxx7-pwpg",
        "GO-2026-5415"
      ],
      "metrics": [
        {
          "type": "CVSS_V4",
          "score": "CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N"
        }
      ],
      "affected": [
        {
          "ranges": [
            {
              "type": "SEMVER",
              "events": [
                {
                  "introduced": "0.0.0-20180815103019-7c14cdb60e53"
                }
              ]
            }
          ],
          "package": {
            "name": "github.com/minio/minio",
            "purl": "pkg:golang/github.com/minio/minio",
            "ecosystem": "Go"
          },
          "database_specific": {
            "source": "https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2026/04/GHSA-h749-fxx7-pwpg/GHSA-h749-fxx7-pwpg.json"
          }
        }
      ],
      "modified": "2026-10-08T08:11:02.463283739Z",
      "provider": "osv",
      "references": [
        "https://github.com/minio/minio/security/advisories/GHSA-h749-fxx7-pwpg",
        "https://nvd.nist.gov/vuln/detail/CVE-2026-39414",
        "https://github.com/minio/minio/pull/8200",
        "https://github.com/minio/minio/commit/7c14cdb60e53dbfdad2be644dfb180cab19fffa7",
        "https://docs.min.io/enterprise/aistor-object-store/upgrade-aistor-server/community-edition",
        "https://github.com/minio/minio",
        "https://pkg.go.dev/vuln/GO-2026-5415?q"
      ],
      "provider_metadata": {
        "cwe_ids": [
          "CWE-770"
        ],
        "severity": "HIGH",
        "github_reviewed": true,
        "nvd_published_at": "2026-04-08T21:16:58Z",
        "github_reviewed_at": "2026-04-09T17:32:31Z"
      }
    },
    "related_cves": [
      {
        "value": "CVE-2026-39414",
        "evidence": "/aliases"
      }
    ],
    "security_relevant": true,
    "severity_evidence": "/database_specific/severity"
  },
  "source_id": "core-osv",
  "document_id": 98768,
  "published_at": "2026-04-09T17:32:31+00:00"
}