Security advisory

{
  "id": "eae77c9370379a5f0bc931fe80224d3b39b4001ddb0e868035fab39e08668de5",
  "url": "https://osv.dev/vulnerability/CVE-2020-21048",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "CVE-2020-21048",
    "summary": "An issue in the dither.c component of libsixel prior to v1.8.4 allows attackers to cause a denial of service (DOS) via a crafted PNG file.",
    "evidence": "osv:CVE-2020-21048",
    "products": [],
    "severity": "medium",
    "structured": {
      "id": "CVE-2020-21048",
      "aliases": [
        "CVE-2020-21048"
      ],
      "metrics": [
        {
          "type": "CVSS_V3",
          "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H"
        }
      ],
      "affected": [
        {
          "ranges": [
            {
              "repo": "https://github.com/saitoha/libsixel",
              "type": "GIT",
              "events": [
                {
                  "introduced": "0"
                },
                {
                  "fixed": "686d234ae20f97b9d816d4147ba3f4b90dbae72e"
                },
                {
                  "fixed": "cb373ab6614c910407c5e5a93ab935144e62b037"
                }
              ],
              "database_specific": {
                "extracted_events": [
                  {
                    "cpe": "cpe:2.3:a:saitoha:libsixel:*:*:*:*:*:*:*:*",
                    "range": [
                      {
                        "introduced": "0"
                      },
                      {
                        "fixed": "1.8.4"
                      }
                    ],
                    "source": "CPE_RANGE"
                  },
                  {
                    "range": [
                      {
                        "fixed": "cb373ab6614c910407c5e5a93ab935144e62b037"
                      }
                    ],
                    "source": "REFERENCES_COMMIT"
                  },
                  {
                    "range": [
                      {
                        "fixed": "686d234ae20f97b9d816d4147ba3f4b90dbae72e"
                      }
                    ],
                    "source": "REFERENCES_TAG",
                    "original_tag": "v1.8.4"
                  }
                ]
              }
            }
          ],
          "versions": [
            "v1.8.3",
            "v1.8.2",
            "v1.8.1",
            "v1.8.0",
            "v1.7.3",
            "v1.7.2",
            "v1.7.1",
            "v1.6.1",
            "v1.5.2",
            "v1.5.1",
            "v1.5.0",
            "v1.4.13",
            "v1.4.12",
            "v1.4.11",
            "v1.4.10",
            "v1.4.9",
            "v1.4.8",
            "v1.4.7",
            "v1.4.6",
            "v1.4.5",
            "v1.4.4",
            "v1.4.3",
            "v1.4.2",
            "v1.4.1",
            "v1.4.0",
            "v1.3.6",
            "v1.3.5",
            "v1.3.4",
            "v1.3.3",
            "v1.3.2",
            "v1.3.1",
            "v1.1.2",
            "v1.1.1",
            "v1.1.0",
            "v1.0.2",
            "v1.0.1",
            "v1.0.0",
            "v0.28.0",
            "v0.27.1",
            "v0.27.0",
            "v0.26.0",
            "v0.25.5",
            "v0.25.4",
            "v0.25.3",
            "v0.25.2",
            "v0.25.1",
            "v0.25.0",
            "v0.24.2",
            "v0.24.0",
            "v0.23.2",
            "v0.23.1",
            "v0.23.0",
            "v0.22.3",
            "v0.22.2",
            "v0.22.1",
            "v0.22.0",
            "v0.21.1",
            "v0.21.0",
            "v0.20.0",
            "v0.19.6",
            "v0.19.5",
            "v0.19.4",
            "v0.19.3",
            "v0.19.2",
            "v0.18.0",
            "v0.17.2",
            "v0.17.1",
            "v0.17.0",
            "v0.16.1",
            "v0.16.0",
            "v0.15.0",
            "v0.14.0"
          ],
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2020-21048.json",
            "vanir_signatures": [
              {
                "id": "CVE-2020-21048-3f5e5c8e",
                "digest": {
                  "length": 1607,
                  "function_hash": "219832859337229444931238207892599109504"
                },
                "source": "https://github.com/saitoha/libsixel/commit/cb373ab6614c910407c5e5a93ab935144e62b037",
                "target": {
                  "file": "src/dither.c",
                  "function": "sixel_dither_new"
                },
                "deprecated": false,
                "signature_type": "Function",
                "signature_version": "v1"
              },
              {
                "id": "CVE-2020-21048-b2b72c87",
                "digest": {
                  "threshold": 0.9,
                  "line_hashes": [
                    "199361631072483740361989714307393008478",
                    "291343961692008382086549080687427033920",
                    "16784547706756229315325119660300077615",
                    "101018793880447773360178885930836492685",
                    "69736891406652933996193619171756760618",
                    "254643536321277286518119263644437622942",
                    "115812485349409838505546949009351511461"
                  ]
                },
                "source": "https://github.com/saitoha/libsixel/commit/cb373ab6614c910407c5e5a93ab935144e62b037",
                "target": {
                  "file": "src/dither.c"
                },
                "deprecated": false,
                "signature_type": "Line",
                "signature_version": "v1"
              }
            ],
            "vanir_signatures_modified": "2026-10-20T13:52:23Z"
          }
        }
      ],
      "modified": "2026-10-20T13:52:23.005807108Z",
      "provider": "osv",
      "references": [
        "https://github.com/saitoha/libsixel/blob/master/ChangeLog",
        "https://github.com/saitoha/libsixel/releases/tag/v1.8.4",
        "https://bitbucket.org/netbsd/pkgsrc/commits/6f0c011cbfccdffa635d04c84433b1a02687adad",
        "https://github.com/saitoha/libsixel/commit/cb373ab6614c910407c5e5a93ab935144e62b037",
        "https://github.com/saitoha/libsixel/issues/73"
      ],
      "provider_metadata": {}
    },
    "related_cves": [
      {
        "value": "CVE-2020-21048",
        "evidence": "/id"
      }
    ],
    "security_relevant": true,
    "severity_evidence": "/severity/0/score"
  },
  "source_id": "core-osv",
  "document_id": 388310,
  "published_at": "2021-09-14T16:15:08.403+00:00"
}