---
id: "CVE-2026-119121"
kind: "vulnerability"
aliases: ["CVE-2026-119121"]
title: "Crawl4AI: authenticated API users can run JavaScript in crawled pages"
severity: "medium"
cvss: 5.3
epss: null
exploited: false
status: "open"
category: "ai-tooling"
products: []
ecosystems: []
tags: ["ai-tooling", "crawl4ai", "docker", "python"]
not_affected_if: ["api-server-not-deployed", "library-only-use", "version-0.9.5-or-later"]
published_at: "2026-10-29T16:18:04+00:00"
first_seen_at: "2026-10-29T16:25:58+00:00"
updated_at: "2026-10-29T16:31:53+00:00"
sources: [{"source": "nvd", "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-119121", "first_seen_at": "2026-10-29T16:25:58+00:00"}]
---

# Crawl4AI: authenticated API users can run JavaScript in crawled pages

Crawl4AI versions from 0.9.0 before 0.9.5 let an authenticated client of the Docker API server inject JavaScript through the css_selector and wait_for fields. The injected script runs in the crawled page, so an attacker can alter page state and the content the crawl returns.

_Summary, check and fix written by a model from the sources; labelled as such._

## How to check

- Check the installed Crawl4AI version, for example with `pip show crawl4ai` or the image tag of the Docker deployment.
- Confirm whether the Docker API server is reachable by clients outside your trusted group.

## Fix

- Crawl4AI `0.9.5` or later, per the advisory's fixed range (from 0.9.0 before 0.9.5 is affected).

## Timeline

- 2026-10-29T16:25:58+00:00 nvd https://nvd.nist.gov/vuln/detail/CVE-2026-119121

## From the sources

Crawl4AI from 0.9.0 before 0.9.5 contains a JavaScript injection vulnerability in the Docker API server that allows authenticated API clients to run arbitrary JavaScript in the crawl page via allowlisted css_selector and wait_for fields. Attackers can inject quotes into css_selector or supply js: conditions in wait_for, bypassing the js_code block to alter page state and returned crawl content.

---

_Free to read at a human pace. An API with keys and an MCP server are in preparation; early access: hello@infrastack.ai_