github.com/gomarkdown/markdown Out-of-bounds Read while parsing citations

{
  "id": "62db6ccbe6c771cf5372a39bd0d1ff0660463091576a232a9e3b6cdb8c615f42",
  "url": "https://osv.dev/vulnerability/CVE-2023-42821",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "github.com/gomarkdown/markdown Out-of-bounds Read while parsing citations",
    "summary": "The package `github.com/gomarkdown/markdown` is a Go library for parsing Markdown text and rendering as HTML. Prior to pseudoversion `0.0.0-20230922105210-14b16010c2ee`, which corresponds with commit `14b16010c2ee7ff33a940a541d993bd043a88940`, parsing malformed markdown input with parser that uses parser.Mmark extension could result in out-of-bounds read vulnerability. To exploit the vulnerability, parser needs to have `parser.Mmark` extension set. The panic occurs inside the `citation.go` file on the line 69 when the parser tries to access the element past its length. This can result in a denial of service. Commit `14b16010c2ee7ff33a940a541d993bd043a88940`/pseudoversion `0.0.0-20230922105210-14b16010c2ee` contains a patch for this issue.",
    "evidence": "osv:CVE-2023-42821",
    "products": [],
    "severity": "high",
    "structured": {
      "id": "CVE-2023-42821",
      "aliases": [
        "CVE-2023-42821",
        "GHSA-m9xq-6h2j-65r2",
        "GO-2023-2074"
      ],
      "metrics": [
        {
          "type": "CVSS_V3",
          "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H"
        }
      ],
      "affected": [
        {
          "ranges": [
            {
              "repo": "https://github.com/gomarkdown/markdown",
              "type": "GIT",
              "events": [
                {
                  "introduced": "0"
                },
                {
                  "fixed": "14b16010c2ee7ff33a940a541d993bd043a88940"
                }
              ],
              "database_specific": {
                "extracted_events": [
                  {
                    "range": [
                      {
                        "fixed": "14b16010c2ee7ff33a940a541d993bd043a88940"
                      }
                    ],
                    "source": "REFERENCES_COMMIT"
                  }
                ]
              }
            }
          ],
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2023-42821.json"
          }
        }
      ],
      "modified": "2026-10-28T02:30:46.514837153Z",
      "provider": "osv",
      "references": [
        "https://github.com/gomarkdown/markdown/blob/7478c230c7cd3e7328803d89abe591d0b61c41e4/parser/citation.go#L69",
        "https://github.com/CVEProject/cvelistV5/tree/main/cves/2023/42xxx/CVE-2023-42821.json",
        "https://github.com/gomarkdown/markdown/security/advisories/GHSA-m9xq-6h2j-65r2",
        "https://nvd.nist.gov/vuln/detail/CVE-2023-42821",
        "https://github.com/gomarkdown/markdown/commit/14b16010c2ee7ff33a940a541d993bd043a88940"
      ],
      "provider_metadata": {
        "cwe_ids": [
          "CWE-125"
        ],
        "cna_assigner": "GitHub_M",
        "unresolved_ranges": [
          {
            "extracted_events": [
              {
                "range": [
                  {
                    "fixed": "0.0.0-20230922105210-14b16010c2ee"
                  }
                ],
                "source": "AFFECTED_FIELD",
                "strategy": "StringRangeExpression"
              }
            ]
          }
        ],
        "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2023/42xxx/CVE-2023-42821.json"
      }
    },
    "related_cves": [
      {
        "value": "CVE-2023-42821",
        "evidence": "/id"
      }
    ],
    "security_relevant": true,
    "severity_evidence": "/severity/0/score"
  },
  "source_id": "core-osv",
  "document_id": 514610,
  "published_at": "2023-09-22T16:55:33.355+00:00"
}