PYSEC-2026-558

Vulnerability from pysec - Published: 2026-06-29 11:50 - Updated: 2026-06-29 12:05
VLAI
Details

A Path Traversal vulnerability in the partition_msg function allows an attacker to write or overwrite arbitrary files on the filesystem when processing malicious MSG files with attachments.

## Impact An attacker can craft a malicious .msg file with attachment filenames containing path traversal sequences (e.g., ../../../etc/cron.d/malicious). When processed with process_attachments=True, the library writes the attachment to an attacker-controlled path, potentially leading to:

  • Arbitrary file overwrite
  • Remote code execution (via overwriting configuration files, cron jobs, or Python packages)
  • Data corruption
  • Denial of service

## Affected Functionality The vulnerability affects the MSG file partitioning functionality when process_attachments=True is enabled.

## Vulnerability Details The library does not sanitize attachment filenames in MSG files before using them in file write operations, allowing directory traversal sequences to escape the intended output directory.

## Workarounds Until patched, users can: - Set process_attachments=False when processing untrusted MSG files - Avoid processing MSG files from untrusted sources - Implement additional filename validation before processing

Impacted products
Name purl
unstructured

{
  "affected": [
    {
      "database_specific": {
        "last_known_affected_version_range": "\u003c= 0.18.17"
      },
      "package": {
        "ecosystem": "PyPI",
        "name": "unstructured"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "0.18.18"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "0.0.1.dev0",
        "0.10.0",
        "0.10.1",
        "0.10.10",
        "0.10.11",
        "0.10.12",
        "0.10.13",
        "0.10.14",
        "0.10.15",
        "0.10.16",
        "0.10.18",
        "0.10.19",
        "0.10.19.dev18",
        "0.10.2",
        "0.10.20",
        "0.10.21",
        "0.10.22",
        "0.10.23",
        "0.10.24",
        "0.10.25",
        "0.10.26",
        "0.10.27",
        "0.10.28",
        "0.10.29",
        "0.10.30",
        "0.10.4",
        "0.10.5",
        "0.10.6",
        "0.10.7",
        "0.10.8",
        "0.10.9",
        "0.11.0",
        "0.11.1",
        "0.11.2",
        "0.11.4",
        "0.11.5",
        "0.11.6",
        "0.11.7",
        "0.11.8",
        "0.12.0",
        "0.12.2",
        "0.12.3",
        "0.12.4",
        "0.12.5",
        "0.12.6",
        "0.13.0",
        "0.13.1",
        "0.13.2",
        "0.13.3",
        "0.13.4",
        "0.13.5",
        "0.13.6",
        "0.13.7",
        "0.14.0",
        "0.14.10",
        "0.14.2",
        "0.14.2.dev1",
        "0.14.3",
        "0.14.4",
        "0.14.5",
        "0.14.6",
        "0.14.7",
        "0.14.8",
        "0.14.9",
        "0.15.0",
        "0.15.1",
        "0.15.10",
        "0.15.12",
        "0.15.13",
        "0.15.14",
        "0.15.3",
        "0.15.5",
        "0.15.6",
        "0.15.7",
        "0.15.8",
        "0.15.9",
        "0.16.0",
        "0.16.1",
        "0.16.10",
        "0.16.11",
        "0.16.12",
        "0.16.13",
        "0.16.14",
        "0.16.15",
        "0.16.16",
        "0.16.17",
        "0.16.19",
        "0.16.2",
        "0.16.20",
        "0.16.21",
        "0.16.22",
        "0.16.23",
        "0.16.24",
        "0.16.25",
        "0.16.3",
        "0.16.4",
        "0.16.5",
        "0.16.6",
        "0.16.7",
        "0.16.8",
        "0.16.9",
        "0.17.0",
        "0.17.2",
        "0.18.1",
        "0.18.11",
        "0.18.13",
        "0.18.14",
        "0.18.15",
        "0.18.2",
        "0.18.3",
        "0.18.5",
        "0.18.6",
        "0.18.7",
        "0.18.9",
        "0.2.0",
        "0.2.1",
        "0.2.2",
        "0.2.3",
        "0.2.4",
        "0.2.5",
        "0.2.6.dev1",
        "0.3.0",
        "0.3.1",
        "0.3.2",
        "0.3.3",
        "0.3.4",
        "0.3.5",
        "0.4.0",
        "0.4.1",
        "0.4.10",
        "0.4.11",
        "0.4.12",
        "0.4.13",
        "0.4.14",
        "0.4.15",
        "0.4.16",
        "0.4.2",
        "0.4.3",
        "0.4.4",
        "0.4.6",
        "0.4.7",
        "0.4.8",
        "0.4.9",
        "0.5.0",
        "0.5.1",
        "0.5.10",
        "0.5.11",
        "0.5.12",
        "0.5.13",
        "0.5.2",
        "0.5.3",
        "0.5.4",
        "0.5.6",
        "0.5.7",
        "0.5.8",
        "0.5.9",
        "0.6.0",
        "0.6.1",
        "0.6.10",
        "0.6.11",
        "0.6.2",
        "0.6.3",
        "0.6.4",
        "0.6.5",
        "0.6.6",
        "0.6.7",
        "0.6.8",
        "0.6.9",
        "0.7.0",
        "0.7.1",
        "0.7.10",
        "0.7.11",
        "0.7.12",
        "0.7.2",
        "0.7.3",
        "0.7.4",
        "0.7.5",
        "0.7.6",
        "0.7.7",
        "0.7.8",
        "0.7.9",
        "0.8.0",
        "0.8.1",
        "0.8.3",
        "0.8.4",
        "0.8.5",
        "0.8.6",
        "0.8.7",
        "0.8.8",
        "0.9.0",
        "0.9.1",
        "0.9.2",
        "0.9.3"
      ]
    }
  ],
  "aliases": [
    "CVE-2025-64712",
    "GHSA-gm8q-m8mv-jj5m"
  ],
  "details": "A Path Traversal vulnerability in the `partition_msg` function allows an attacker to write or overwrite arbitrary files on the filesystem when processing malicious MSG files with attachments.\n\n  ## Impact\n  An attacker can craft a malicious .msg file with attachment filenames containing path traversal sequences (e.g.,\n  `../../../etc/cron.d/malicious`). When processed with `process_attachments=True`, the library writes the attachment to an\n  attacker-controlled path, potentially leading to:\n\n  - Arbitrary file overwrite\n  - Remote code execution (via overwriting configuration files, cron jobs, or Python packages)\n  - Data corruption\n  - Denial of service\n\n  ## Affected Functionality\n  The vulnerability affects the MSG file partitioning functionality when `process_attachments=True` is enabled.\n\n  ## Vulnerability Details\n  The library does not sanitize attachment filenames in MSG files before using them in file write operations, allowing directory\n  traversal sequences to escape the intended output directory.\n\n  ## Workarounds\n  Until patched, users can:\n  - Set `process_attachments=False` when processing untrusted MSG files\n  - Avoid processing MSG files from untrusted sources\n  - Implement additional filename validation before processing",
  "id": "PYSEC-2026-558",
  "modified": "2026-06-29T12:05:50.985804Z",
  "published": "2026-06-29T11:50:51.107727Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/Unstructured-IO/unstructured/security/advisories/GHSA-gm8q-m8mv-jj5m"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2025-64712"
    },
    {
      "type": "WEB",
      "url": "https://github.com/Unstructured-IO/unstructured/commit/b01d35b2373fd087d2e15162b9c021663c97155d"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/Unstructured-IO/unstructured"
    },
    {
      "type": "PACKAGE",
      "url": "https://pypi.org/project/unstructured"
    },
    {
      "type": "ADVISORY",
      "url": "https://github.com/advisories/GHSA-gm8q-m8mv-jj5m"
    }
  ],
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H",
      "type": "CVSS_V3"
    }
  ],
  "summary": "Unstructured has Path Traversal via Malicious MSG Attachment that Allows Arbitrary File Write"
}


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