Security advisory

{
  "id": "29e3d3540e16f3cbbf292c9a8614b083b3d8c2c2cb95180edf10a726cb5dca85",
  "url": "https://osv.dev/vulnerability/CVE-2021-28856",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "CVE-2021-28856",
    "summary": "In Deark before v1.5.8, a specially crafted input file can cause a division by zero in (src/fmtutil.c) because of the value of pixelsize.",
    "evidence": "osv:CVE-2021-28856",
    "products": [],
    "severity": "medium",
    "structured": {
      "id": "CVE-2021-28856",
      "aliases": [
        "CVE-2021-28856"
      ],
      "metrics": [
        {
          "type": "CVSS_V3",
          "score": "CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H"
        }
      ],
      "affected": [
        {
          "ranges": [
            {
              "repo": "https://github.com/jsummers/deark",
              "type": "GIT",
              "events": [
                {
                  "introduced": "0"
                },
                {
                  "fixed": "fb671aa5d1b4317fabe5aab3e3713ca4b5798f95"
                },
                {
                  "fixed": "62acb7753b0e3c0d3ab3c15057b0a65222313334"
                }
              ],
              "database_specific": {
                "extracted_events": [
                  {
                    "cpe": "cpe:2.3:a:entropymine:deark:*:*:*:*:*:*:*:*",
                    "range": [
                      {
                        "introduced": "0"
                      },
                      {
                        "fixed": "1.5.8"
                      }
                    ],
                    "source": "CPE_RANGE"
                  },
                  {
                    "range": [
                      {
                        "fixed": "62acb7753b0e3c0d3ab3c15057b0a65222313334"
                      }
                    ],
                    "source": "REFERENCES_COMMIT"
                  }
                ]
              }
            }
          ],
          "versions": [
            "v1.5.7",
            "v1.5.6",
            "v1.5.5"
          ],
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2021-28856.json",
            "vanir_signatures": [
              {
                "id": "CVE-2021-28856-20c93b3c",
                "digest": {
                  "length": 1711,
                  "function_hash": "248262192169236894308598232324636050185"
                },
                "source": "https://github.com/jsummers/deark/commit/62acb7753b0e3c0d3ab3c15057b0a65222313334",
                "target": {
                  "file": "src/fmtutil.c",
                  "function": "fmtutil_macbitmap_read_pixmap_only_fields"
                },
                "deprecated": false,
                "signature_type": "Function",
                "signature_version": "v1"
              },
              {
                "id": "CVE-2021-28856-a2b20c9c",
                "digest": {
                  "threshold": 0.9,
                  "line_hashes": [
                    "244882389384385273642324215724738835063",
                    "307193932932608575538273208167705831698",
                    "139963083082355081054987694254954411722",
                    "181154449912201028302768243979563471015"
                  ]
                },
                "source": "https://github.com/jsummers/deark/commit/62acb7753b0e3c0d3ab3c15057b0a65222313334",
                "target": {
                  "file": "src/fmtutil.c"
                },
                "deprecated": false,
                "signature_type": "Line",
                "signature_version": "v1"
              }
            ],
            "vanir_signatures_modified": "2026-10-20T14:20:31Z"
          }
        }
      ],
      "modified": "2026-10-20T14:20:31.770129930Z",
      "provider": "osv",
      "references": [
        "https://github.com/fuzzing2026/CVE-PoCs/tree/main/deark-CVE-2021-28856",
        "https://fatihhcelik.github.io/posts/Division-By-Zero-Deark/",
        "https://github.com/jsummers/deark/commit/62acb7753b0e3c0d3ab3c15057b0a65222313334"
      ],
      "provider_metadata": {}
    },
    "related_cves": [
      {
        "value": "CVE-2021-28856",
        "evidence": "/id"
      }
    ],
    "security_relevant": true,
    "severity_evidence": "/severity/0/score"
  },
  "source_id": "core-osv",
  "document_id": 388814,
  "published_at": "2021-04-14T17:15:14.427+00:00"
}