# CVE-2026-43979: Local Deep Research: HTML Injection via Unescaped User Input in PDF Export (`pdf_service.py:_markdown_to_html`)

> An authenticated attacker can inject HTML into PDF exports to trigger Server-Side Request Forgery, bypassing existing defenses and potentially accessing internal resources.

- **Severity:** Medium 5.0 (`CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:L/I:N/A:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Any signed-in user
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 28 May 2026
- **Updated:** 28 May 2026
- **Also known as:** GHSA-fj2m-qvh9-jq4q, PYSEC-2026-2610

## What is CVE-2026-43979?

CVE-2026-43979 is a medium-severity server-side request forgery vulnerability in LearningCircuit local-deep-research, published on 28 May 2026. Any signed-in user can exploit it over the network, with no action from the victim.

### Official 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.

Weakness: CWE-918 (Server-Side Request Forgery), CWE-79 (Improper Neutralization of Input During Web Page Generation)

## Which versions are affected by CVE-2026-43979?

3 open source packages ship an affected version, including local-deep-research.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `local-deep-research` | PyPI | All versions | 1.6.0 |
| `local-deep-research` | PyPI | All versions | 1.6.0 |
| `local-deep-research` | PyPI | All versions | 1.6.0 |

## How do I fix CVE-2026-43979?

Upgrade local-deep-research to 1.6.0 or later.

## Is CVE-2026-43979 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-43979 exists.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-43979 and fix it if it is affected.

What it is: CVE-2026-43979 is a medium-severity server-side request forgery vulnerability in LearningCircuit local-deep-research, published on 28 May 2026. Any signed-in user can exploit it over the network, with no action from the victim.
Exploitation: It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-43979 exists.

Affected packages and fixed versions:
- local-deep-research (PyPI): affected all versions; fixed in 1.6.0
- local-deep-research (PyPI): affected all versions; fixed in 1.6.0
- local-deep-research (PyPI): affected all versions; fixed in 1.6.0

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-43979/ (Markdown: https://insights.sbomify.com/CVE-2026-43979/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-43979
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-43979
- OSV: https://osv.dev/vulnerability/CVE-2026-43979

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-43979/
Summaries are generated and may contain mistakes; the official description above is the record.