# CVE-2026-105743: Docling DNS rebinding in URL validation and HTML rendering

Source: https://junglewise.ai/threats/cve-2026-105743-docling-simplifies-document-processing-by-parsing-diverse  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-10-05. Updated: 2026-10-05  
License: CC BY 4.0 with a link back

CVE-2026-105743 · Severity: medium · CVSS 4 · Published 2026-10-05

Docling is a document processing library that converts diverse file formats into structured data for AI applications. When remote fetching is enabled, attackers can bypass URL safety checks through DNS rebinding and other DNS tricks to reach internal services, potentially exposing sensitive data if the fetched content is decoded as an image or rendered in screenshots.

Technologies: [Docling Project Docling](https://junglewise.ai/threats/technologies/docling-project-docling), [docling (PyPI)](https://junglewise.ai/threats/technologies/pypi-docling), [docling-slim (PyPI)](https://junglewise.ai/threats/technologies/docling-slim). Vendors: [Docling Project](https://junglewise.ai/threats/vendors/docling-project), [PyPI](https://junglewise.ai/threats/vendors/pypi).

## Quick answers

**Is CVE-2026-105743 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-105743 being exploited in the wild.

**How severe is CVE-2026-105743?** Medium severity, with a CVSS score of 4, published 5 October 2026.

**Which products and versions are affected?** Docling Project Docling from 2.91.0 until 2.132.0; docling (PyPI) >= 2.91.0, < 2.132.0, ECOSYSTEM:introduced=2.91.0,fixed=2.132.0; docling-slim (PyPI) >= 2.92.0, < 2.132.0, ECOSYSTEM:introduced=2.92.0,fixed=2.132.0.

**Is there a fix for CVE-2026-105743?** Yes. docling (PyPI): upgrade to 2.132.0 or later; docling-slim (PyPI): upgrade to 2.132.0 or later. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

**How is CVE-2026-105743 attacked?** It is attacked over the network, in a software library.

**Am I affected by CVE-2026-105743?** Check whether you run Docling Project Docling, docling (PyPI) or docling-slim (PyPI) at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## How to fix

- docling (PyPI): upgrade to 2.132.0 or later

  ```sh
  pip install "docling>=2.132.0"
  ```

- docling-slim (PyPI): upgrade to 2.132.0 or later

  ```sh
  pip install "docling-slim>=2.132.0"
  ```


## Technical details

The validate_url_safety function in docling/backend/utils/image_resource_loader.py performs a single DNS lookup to validate a hostname, but then allows the HTTP client to perform its own DNS resolution, enabling DNS rebinding attacks. The vulnerability also affects HTMLBackendOptions(render_page=True), which allows unchecked browser requests to internal destinations. Exploitation requires remote fetching to be enabled, and exposure occurs only when response content is decoded as an image or passively rendered in a page screenshot.

## Affected products

- Docling Project Docling from 2.91.0 until 2.132.0

## Identifiers

- CVE-2026-105743
- GHSA-pc36-qwjq-x68c
- PYSEC-2026-4190
- PYSEC-2026-4214

## Timeline

- 2026-10-05: disclosed
- 2026-09-29: patched

## References

- [https://github.com/docling-project/docling/commit/5e469137f275ffc443306a30d12a3a45bceb80fb](https://github.com/docling-project/docling/commit/5e469137f275ffc443306a30d12a3a45bceb80fb)
- [https://github.com/docling-project/docling/pull/4420](https://github.com/docling-project/docling/pull/4420)

## Related threats

- [Docling METS-GBS archive member limit enforced after full enumeration](https://junglewise.ai/threats/duplicate-advisory-docling-mets-gbs-archive-member-limit-enforced-after-087423a8)
- [Docling arbitrary filesystem read via unvalidated xlink:href in ODF images](https://junglewise.ai/threats/cve-2026-105751-docling-simplifies-document-processing-by-parsing-diverse)
- [Docling local file disclosure in HTML rendering](https://junglewise.ai/threats/cve-2026-105750-docling-simplifies-document-processing-by-parsing-diverse)
- [Docling unbounded table span allocation denial of service](https://junglewise.ai/threats/cve-2026-105749-docling-simplifies-document-processing-by-parsing-diverse)
- [IBM Docling arbitrary local file read via JSON backend](https://junglewise.ai/threats/cve-2026-105748-docling-simplifies-document-processing-by-parsing-diverse)