Unfurl < 2026.04 - Denial of Service via Unbounded zlib Decompression

{
  "id": "f4046870beb9a8fb6621747848f35851094c64c47f52519d09dbe378170e56f2",
  "url": "https://osv.dev/vulnerability/CVE-2026-40036",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "Unfurl < 2026.04 - Denial of Service via Unbounded zlib Decompression",
    "summary": "Unfurl before 2026.04 contains an unbounded zlib decompression vulnerability in parse_compressed.py that allows remote attackers to cause denial of service. Attackers can submit highly compressed payloads via URL parameters to the /json/visjs endpoint that expand to gigabytes, exhausting server memory and crashing the service.",
    "evidence": "osv:CVE-2026-40036",
    "products": [],
    "severity": "high",
    "structured": {
      "id": "CVE-2026-40036",
      "aliases": [
        "CVE-2026-40036",
        "GHSA-h5qv-qjv4-pc5m",
        "PYSEC-2026-1294"
      ],
      "metrics": [
        {
          "type": "CVSS_V4",
          "score": "CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N"
        }
      ],
      "affected": [
        {
          "ranges": [
            {
              "repo": "https://github.com/RyanDFIR/unfurl",
              "type": "GIT",
              "events": [
                {
                  "introduced": "0"
                },
                {
                  "fixed": "ae801d5fba62777d601e39b25e06ac102fafa4ec"
                }
              ],
              "database_specific": {
                "extracted_events": [
                  {
                    "range": [
                      {
                        "introduced": "0"
                      },
                      {
                        "fixed": "2026.04"
                      }
                    ],
                    "source": "AFFECTED_FIELD",
                    "strategy": "StandardRange"
                  },
                  {
                    "cpe": "cpe:2.3:a:ryandfir:unfurl:*:*:*:*:*:*:*:*",
                    "range": [
                      {
                        "introduced": "0"
                      },
                      {
                        "fixed": "2026.04"
                      }
                    ],
                    "source": "CPE_RANGE"
                  },
                  {
                    "range": [
                      {
                        "fixed": "ae801d5fba62777d601e39b25e06ac102fafa4ec"
                      }
                    ],
                    "source": "REFERENCES_TAG",
                    "original_tag": "v2026.04"
                  }
                ]
              }
            }
          ],
          "versions": [
            "v2025.08",
            "v2025.03",
            "v2025.02",
            "v2024.11",
            "v2024.11.20",
            "v2024.06.27",
            "v2024.06.26",
            "v2024.06",
            "v2023.09.05",
            "v2023.09.04",
            "v2023.09.03",
            "v2023.09.02",
            "v2023.09.01",
            "v2023.09",
            "v2022.11.01",
            "v2022.11",
            "v2022.02",
            "v2021.06.15",
            "v2021.03.11",
            "20201102",
            "20200812"
          ],
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-40036.json"
          }
        }
      ],
      "modified": "2026-10-28T02:30:52.824528705Z",
      "provider": "osv",
      "references": [
        "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/40xxx/CVE-2026-40036.json",
        "https://github.com/obsidianforensics/unfurl/security/advisories/GHSA-h5qv-qjv4-pc5m",
        "https://nvd.nist.gov/vuln/detail/CVE-2026-40036",
        "https://www.vulncheck.com/advisories/dfir-unfurl-denial-of-service-via-unbounded-zlib-decompression",
        "https://github.com/obsidianforensics/unfurl/releases/tag/v2026.04",
        "https://github.com/obsidianforensics/unfurl"
      ],
      "provider_metadata": {
        "cwe_ids": [
          "CWE-409",
          "CWE-770"
        ],
        "cna_assigner": "VulnCheck",
        "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/40xxx/CVE-2026-40036.json"
      }
    },
    "related_cves": [
      {
        "value": "CVE-2026-40036",
        "evidence": "/id"
      }
    ],
    "security_relevant": true,
    "severity_evidence": "/severity/0/score"
  },
  "source_id": "core-osv",
  "document_id": 521824,
  "published_at": "2026-04-08T21:35:28.46+00:00"
}