GHSA-7cx2-g3h9-382p: Crawl4AI Arbitrary File Write (symlink/TOCTOU) Plus Vulnerability

{
  "schema_version" : "1.4.0",
  "id" : "GHSA-7cx2-g3h9-382p",
  "modified" : "2026-07-21T15:02:21Z",
  "published" : "2026-06-16T21:02:19Z",
  "aliases" : [ ],
  "summary" : "Crawl4AI: Arbitrary file write (symlink/TOCTOU) plus log and webhook-header injection in Docker server",
  "details" : "### Summary\n\nThree backward-compatible hardening fixes in the Docker API server. The headline issue is an arbitrary file write via the screenshot/PDF `output_path`.\n\n### 1. Arbitrary file write via output_path symlink / TOCTOU (primary)\n\n`POST /screenshot` and `POST /pdf` accept an `output_path` constrained to `ALLOWED_OUTPUT_DIR` by `validate_output_path`. The 0.8.7 check was string-only: it did not resolve symlinks, so a symlinked path component inside the output directory could redirect the write outside the directory, and the final `open()` followed symlinks. On a deployment where the runtime user can write executable/cron locations this is an arbitrary-write to code-execution primitive. The API is unauthenticated by default.\n\nFix: `validate_output_path` now resolves the real path (symlinks) of the parent and re-checks containment, and the write uses `O_NOFOLLOW` (`write_output_file`). `output_path` remains supported.\n\n### 2. CRLF log injection (CWE-117)\n\nUser-controlled URLs/errors reflected into log lines could embed CR/LF and forge additional log entries. Fix: a logging filter strips CR/LF/control characters from all records.\n\n### 3. Webhook request-header injection (CWE-93/CWE-113)\n\nUser-supplied webhook headers were sent verbatim, allowing CRLF and hop-by-hop / sensitive header injection on the outbound webhook request. Fix: webhook headers are validated (name pattern, no control characters, deny `Host`/`Content-Length`/`Transfer-Encoding`/`Authorization`/`Cookie`/...), with early request-time rejection.\n\n### Impact\n\nArbitrary file write (potential code execution) for #1; log forging for #2; request smuggling / header injection on outbound webhooks for #3.\n\n### Workarounds\n\n- Upgrade to the patched version.\n- Enable authentication (`CRAWL4AI_API_TOKEN`).\n- Run the container with a read-only root filesystem.\n\n### Credits\n\nInternal security audit (Crawl4AI maintainers).",
  "severity" : [ {
    "type" : "CVSS_V3",
    "score" : "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "PyPI",
      "name" : "crawl4ai"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "0"
      }, {
        "fixed" : "0.8.8"
      } ]
    } ],
    "database_specific" : {
      "last_known_affected_version_range" : "<= 0.8.7"
    }
  } ],
  "references" : [ {
    "type" : "WEB",
    "url" : "https://github.com/unclecode/crawl4ai/security/advisories/GHSA-7cx2-g3h9-382p"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/unclecode/crawl4ai/issues/1"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/unclecode/crawl4ai/issues/2"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/unclecode/crawl4ai/pull/3"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/pypa/advisory-database/tree/main/vulns/crawl4ai/PYSEC-2026-228.yaml"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/unclecode/crawl4ai"
  }, {
    "type" : "WEB",
    "url" : "https://www.vulncheck.com/advisories/crawl4ai-arbitrary-file-write-via-output-path-symlink-and-toctou"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-117", "CWE-22", "CWE-59", "CWE-93" ],
    "severity" : "HIGH",
    "github_reviewed" : true,
    "github_reviewed_at" : "2026-06-16T21:02:19Z",
    "nvd_published_at" : null
  }
}