Security advisory

{
  "id": "b2bcc205d06a328b193759338d8096882007f99fe57ec5c3b083b8bcfdf193e1",
  "url": "https://osv.dev/vulnerability/CVE-2021-3751",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "CVE-2021-3751",
    "summary": "libmobi is vulnerable to Out-of-bounds Write",
    "evidence": "osv:CVE-2021-3751",
    "products": [],
    "severity": "critical",
    "structured": {
      "id": "CVE-2021-3751",
      "aliases": [
        "CVE-2021-3751"
      ],
      "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/bfabiszewski/libmobi",
              "type": "GIT",
              "events": [
                {
                  "introduced": "0"
                },
                {
                  "fixed": "c814c4aba4e090fa32805ff8ff459df6c2c61b5c"
                },
                {
                  "fixed": "ab5bf0e37e540eac682a14e628853b918626e72b"
                }
              ],
              "database_specific": {
                "extracted_events": [
                  {
                    "cpe": "cpe:2.3:a:libmobi_project:libmobi:*:*:*:*:*:*:*:*",
                    "range": [
                      {
                        "introduced": "0"
                      },
                      {
                        "fixed": "0.7"
                      }
                    ],
                    "source": "CPE_RANGE"
                  },
                  {
                    "range": [
                      {
                        "fixed": "ab5bf0e37e540eac682a14e628853b918626e72b"
                      }
                    ],
                    "source": "REFERENCES_COMMIT"
                  }
                ]
              }
            }
          ],
          "versions": [
            "v0.6",
            "v0.5",
            "v0.4",
            "v0.3",
            "v0.2"
          ],
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2021-3751.json",
            "vanir_signatures": [
              {
                "id": "CVE-2021-3751-8edb6631",
                "digest": {
                  "threshold": 0.9,
                  "line_hashes": [
                    "120694252244805791903290417316973324711",
                    "120333361470414790212041862905057810084",
                    "242482985265602302095058247358560159784",
                    "120221589808660705953910058901898346551",
                    "253859431149654223752734219259169364840"
                  ]
                },
                "source": "https://github.com/bfabiszewski/libmobi/commit/ab5bf0e37e540eac682a14e628853b918626e72b",
                "target": {
                  "file": "src/buffer.c"
                },
                "deprecated": false,
                "signature_type": "Line",
                "signature_version": "v1"
              },
              {
                "id": "CVE-2021-3751-a9163d0e",
                "digest": {
                  "length": 576,
                  "function_hash": "280190109604768326930381359724459835257"
                },
                "source": "https://github.com/bfabiszewski/libmobi/commit/ab5bf0e37e540eac682a14e628853b918626e72b",
                "target": {
                  "file": "src/buffer.c",
                  "function": "mobi_buffer_move"
                },
                "deprecated": false,
                "signature_type": "Function",
                "signature_version": "v1"
              }
            ],
            "vanir_signatures_modified": "2026-10-20T14:27:09Z"
          }
        }
      ],
      "modified": "2026-10-20T14:27:09.304003561Z",
      "provider": "osv",
      "references": [
        "https://github.com/bfabiszewski/libmobi/commit/ab5bf0e37e540eac682a14e628853b918626e72b",
        "https://huntr.dev/bounties/fcb4383c-bc27-4b89-bfce-6b041f0cb769"
      ],
      "provider_metadata": {}
    },
    "related_cves": [
      {
        "value": "CVE-2021-3751",
        "evidence": "/id"
      }
    ],
    "security_relevant": true,
    "severity_evidence": "/severity/0/score"
  },
  "source_id": "core-osv",
  "document_id": 388998,
  "published_at": "2021-09-15T07:15:06.98+00:00"
}