Security advisory

{
  "id": "9ff9af1c3cd475b67891087b24b08856e1ed5fb3338f4598e2f64e563057ea0b",
  "url": "https://osv.dev/vulnerability/CVE-2020-6839",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "CVE-2020-6839",
    "summary": "In mruby 2.1.0, there is a stack-based buffer overflow in mrb_str_len_to_dbl in string.c.",
    "evidence": "osv:CVE-2020-6839",
    "products": [],
    "severity": "critical",
    "structured": {
      "id": "CVE-2020-6839",
      "aliases": [
        "CVE-2020-6839"
      ],
      "metrics": [
        {
          "type": "CVSS_V3",
          "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H"
        }
      ],
      "affected": [
        {
          "ranges": [
            {
              "repo": "https://github.com/mruby/mruby",
              "type": "GIT",
              "events": [
                {
                  "introduced": "57a56ddaa26d1bb7d67c8dde435b2e08dc17290f"
                },
                {
                  "last_affected": "57a56ddaa26d1bb7d67c8dde435b2e08dc17290f"
                }
              ],
              "database_specific": {
                "extracted_events": [
                  {
                    "cpe": "cpe:2.3:a:mruby:mruby:2.1.0:*:*:*:*:*:*:*",
                    "range": [
                      {
                        "introduced": "2.1.0"
                      },
                      {
                        "last_affected": "2.1.0"
                      }
                    ],
                    "source": "CPE_STRING"
                  }
                ]
              }
            }
          ],
          "versions": [
            "2.1.0"
          ],
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2020-6839.json"
          }
        }
      ],
      "modified": "2026-10-20T10:54:23.341510618Z",
      "provider": "osv",
      "references": [
        "https://github.com/mruby/mruby/issues/4929"
      ],
      "provider_metadata": {}
    },
    "related_cves": [
      {
        "value": "CVE-2020-6839",
        "evidence": "/id"
      }
    ],
    "security_relevant": true,
    "severity_evidence": "/severity/0/score"
  },
  "source_id": "core-osv",
  "document_id": 385263,
  "published_at": "2020-01-11T03:15:11.027+00:00"
}