# CVE-2026-40112: PraisonAI has Stored XSS via Unsanitized Agent Output in HTML Rendering (nh3 Not a Required Dependency)

> Attackers can inject arbitrary JavaScript into PraisonAI agent outputs, leading to stored XSS in browsers viewing the API.

- **Severity:** Medium 5.4 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:L/A:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** A user has to click or open something
- **Fix available:** Yes
- **Published:** 9 Apr 2026
- **Updated:** 14 Apr 2026
- **Also known as:** GHSA-cfg2-mxfj-j6pw, PYSEC-2026-2910

## What is CVE-2026-40112?

CVE-2026-40112 is a medium-severity cross-site scripting vulnerability in MervinPraison PraisonAI, published on 9 Apr 2026. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.

### Official description

PraisonAI is a multi-agent teams system. Prior to 4.5.128, the Flask API endpoint in src/praisonai/api.py renders agent output as HTML without effective sanitization. The _sanitize_html function relies on the nh3 library, which is not listed as a required or optional dependency in pyproject.toml. When nh3 is absent (the default installation), the sanitizer is a no-op that returns HTML unchanged. An attacker who can influence agent input (via RAG data poisoning, web scraping results, or prompt injection) can inject arbitrary JavaScript that executes in the browser of anyone viewing the API output. This vulnerability is fixed in 4.5.128.

Weakness: CWE-79 (Improper Neutralization of Input During Web Page Generation)

## Which versions are affected by CVE-2026-40112?

3 open source packages ship an affected version, including praisonai and PraisonAI. It affects 1 product.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `praisonai` | PyPI | All versions | 4.5.128 |
| `praisonai` | PyPI | All versions | 4.5.128 |
| `PraisonAI` | PyPI | All versions | 4.5.128 |

Products: Praison Praisonai.

## How do I fix CVE-2026-40112?

Upgrade praisonai to 4.5.128 or later.

## Is CVE-2026-40112 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-40112 exists.

## Other vulnerabilities in MervinPraison PraisonAI

- [CVE-2026-39888](https://insights.sbomify.com/CVE-2026-39888/): PraisonAIAgents has a sandbox escape via exception frame traversal in `execute_code` (subprocess mode) (critical 10.0)
- [CVE-2026-41497](https://insights.sbomify.com/CVE-2026-41497/): Incomplete fix for CVE-2026-34935: Command Injection in MervinPraison/PraisonAI (critical 9.8)
- [CVE-2026-40288](https://insights.sbomify.com/CVE-2026-40288/): PraisonAI: Critical RCE via `type: job` workflow YAML (critical 9.8)
- [CVE-2026-39890](https://insights.sbomify.com/CVE-2026-39890/): PraisonAI Affected by Remote Code Execution via YAML Deserialization in Agent Definition Loading (critical 9.8)
- [CVE-2026-34934](https://insights.sbomify.com/CVE-2026-34934/): PraisonAI: Second-Order SQL Injection in `get_all_user_threads` (critical 9.8)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-40112 and fix it if it is affected.

What it is: CVE-2026-40112 is a medium-severity cross-site scripting vulnerability in MervinPraison PraisonAI, published on 9 Apr 2026. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.
Exploitation: It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-40112 exists.

Affected packages and fixed versions:
- praisonai (PyPI): affected all versions; fixed in 4.5.128
- praisonai (PyPI): affected all versions; fixed in 4.5.128
- PraisonAI (PyPI): affected all versions; fixed in 4.5.128

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-2026-40112/ (Markdown: https://insights.sbomify.com/CVE-2026-40112/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-40112
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-40112
- OSV: https://osv.dev/vulnerability/CVE-2026-40112

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-40112/
Summaries are generated and may contain mistakes; the official description above is the record.