---
id: CVE-2026-44020
aliases:
  - GHSA-m88r-rg27-5xfg
  - PYSEC-2026-240
title: 'Docling: Unsafe XML Entity Expansion in USPTO Patent Backend'
summary: 'Docling: Unsafe XML Entity Expansion in USPTO Patent Backend'
severity: high
cvss: 7.5
cvssVector: 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H'
vendor: docling
product: docling
ecosystem: pip
affected:
  - 'docling >= 2.13.0, < 2.74.0'
patched:
  - docling 2.74.0
published: '2026-06-03'
updated: '2026-07-20'
source: OSV
sourceUrl: 'https://osv.dev/vulnerability/GHSA-m88r-rg27-5xfg'
references:
  - url: >-
      https://github.com/docling-project/docling/security/advisories/GHSA-m88r-rg27-5xfg
  - url: 'https://nvd.nist.gov/vuln/detail/CVE-2026-44020'
  - url: 'https://access.redhat.com/security/cve/CVE-2026-44020'
  - url: 'https://bugzilla.redhat.com/show_bug.cgi?id=2492456'
  - url: 'https://github.com/docling-project/docling'
  - url: 'https://github.com/docling-project/docling/releases/tag/v2.74.0'
  - url: >-
      https://github.com/pypa/advisory-database/tree/main/vulns/docling/PYSEC-2026-240.yaml
  - url: >-
      https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-44020.json
tags:
  - osv
  - pip
epss: 0.00601
epssPercentile: 0.46431
ingestedAt: '2026-07-21T19:04:57.348Z'
---

## Overview

### Impact
The USPTO patent XML parser used the standard `xml.sax.parseString()` without protection against XML External Entity (XXE) attacks. An attacker could craft malicious USPTO patent XML files with external entity references that could:
- Read arbitrary files from the server filesystem
- Perform Server-Side Request Forgery (SSRF) attacks
- Cause denial of service through entity expansion (Billion Laughs attack)

The vulnerability affects three USPTO patent format parsers: ICE (v4.x), Grant v2.5, and Application v1.x.

### Patches
Fixed in version 2.74.0. The parser now uses `defusedxml.sax.make_parser()` with secure configuration that blocks external entity resolution (`feature_external_ges=False`, `feature_external_pes=False`) while allowing DTD declarations required by USPTO files. This prevents XXE attacks while maintaining compatibility with the USPTO XML format.

### Workarounds
Avoid processing USPTO patent XML files from untrusted sources. Implement resource limits (memory, CPU time) when processing patent documents.

### References
- Fix release: [v2.74.0](https://github.com/docling-project/docling/releases/tag/v2.74.0)

## Affected packages

- `docling >= 2.13.0, < 2.74.0`

## Remediation

Upgrade to a patched release:

- `docling 2.74.0`