CVE-2025-64712: Unstructured has Path Traversal via Malicious MSG Attachment that Allows Arbitrary File Write

Should you act?

Critical and remotely reachable

No known exploitation yet, but it is network-reachable without credentials. This signal is computed from CISA KEV, EPSS and CVSS data; it is not an editorial verdict.

• No confirmed exploitation. It is not in CISA’s KEV catalog and CISA’s SSVC assessment records no known exploitation. That can change quickly after a public write-up; re-check if you are affected.
• EPSS 0.7%, percentile 51: FIRST’s model estimates a 0.7% chance of exploitation activity in the next 30 days, higher than 51% of all scored CVEs (moderate). EPSS is a probability, not a verdict.
• Remotely reachable with no login and no user interaction. If the vulnerable service is exposed to the internet, prioritize it.
• Only applies if your dependency tree includes unstructured (PyPI) <= 0.18.17, fixed in 0.18.18. Check your lockfile, including transitive dependencies.

What it is

The unstructured library provides open-source components for ingesting and pre-processing images and text documents, such as PDFs, HTML, Word docs, and many more. Prior to version 0.18.18, a path traversal vulnerability in the partitionmsg function allows an attacker to write or overwrite arbitrary files on the filesystem when processing malicious MSG files with attachments. This issue has been patched in version 0.18.18.

From the GitHub advisory

A Path Traversal vulnerability in the partitionmsg 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 processattachments=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 processattachments=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.

Weakness type: CWE-22, CWE-73.

Product: unstructured (PyPI) · Assigned by: GitHub_M · Published: 2026-02-04

Affected and fixed versions

Severity scores

• Attack vector: network (remotely reachable)
• Attack complexity: low
• Privileges required: none (no login)
• User interaction: none
• Scope: unchanged

CVSS measures how bad a flaw is if exploited, not how likely exploitation is. Read it next to the exploitation data below.

Exploitation and urgency

• CISA KEV: not listed (no confirmed in-the-wild exploitation known to CISA).
• CISA SSVC assessment: exploitation none, automatable yes, technical impact total.
• FIRST EPSS (model of 2026-10-21): 0.67% probability of exploitation activity in the next 30 days; percentile 51.

Timeline

• 2026-02-03 — GitHub-reviewed advisory GHSA-gm8q-m8mv-jj5m published (critical)
• 2026-02-04 — CVE record last updated
• 2026-02-04 — CVE record published by GitHub_M

Sources and references

Original sources first. Version and fix details should always be confirmed against the vendor or project advisory.

Vulnerability records

1. GitHub Advisory GHSA-gm8q-m8mv-jj5m github.com
2. CVE.org record CVE-2025-64712 cve.org
3. NVD entry CVE-2025-64712 nvd.nist.gov

Other references from the CVE record and advisory

1. github.com github.com
2. github.com github.com

Critical PyPI advisories · Today’s Security Digest