Docling: Unsafe XML Entity Expansion in USPTO Patent Backend
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
Affected software
Click a technology to see all vulnerabilities affecting it.
| Platform | Package | Vulnerable versions | Fixed in |
|---|---|---|---|
| Python (PyPI) | docling | >= 2.13.0, < 2.74.0 | 2.74.0 |
References
- https://github.com/docling-project/docling/security/advisories/GHSA-m88r-rg27-5xfg
- https://nvd.nist.gov/vuln/detail/CVE-2026-44020
- https://access.redhat.com/errata/RHSA-2026:60520
- https://access.redhat.com/security/cve/CVE-2026-44020
- https://bugzilla.redhat.com/show_bug.cgi?id=2492456
- https://github.com/docling-project/docling
- https://github.com/docling-project/docling/releases/tag/v2.74.0
- https://github.com/pypa/advisory-database/tree/main/vulns/docling/PYSEC-2026-240.yaml
- https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-44020.json
- CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H- Weakness (CWE)
CWE-611, CWE-776- Platform
- Python (PyPI)
- Package
docling- Disclosed
- 03.06.2026
- Updated
- 11.10.2026 15:17
Sources and licenses
OSV / GitHub Advisory Database - PYSEC-2026-240 - PyPA Advisory Database; CC BY 4.0
OSV / GitHub Advisory Database - GHSA-m88r-rg27-5xfg - CC BY 4.0
Vulnerability history: docling
All published vulnerabilities of this package (Python (PyPI)), newest first. Shows whether this is a one-off slip or a package that needs watching.
- Total entries
- 18
- First → latest
- 05.2026 10.2026
- Without a fix
- 2
- Exploited in attacks
- 0
Severity breakdown
- High 7
- Medium 10
- Low 1
Disclosures per year
- 2026: 18
-
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