How severe is CVE-2026-57571?

CVE-2026-57571 has a CVSS score of 9.6/10, rated CRITICAL. Immediate patching is strongly recommended.

Which packages are affected by CVE-2026-57571?

CVE-2026-57571 affects the following packages: crawl4ai (PyPI). Ecosystems affected: PyPI.

How do I fix CVE-2026-57571?

Update crawl4ai to 0.9.0 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-57571 is resolved across your whole dependency graph.

How do I detect CVE-2026-57571 in my PyPI dependencies?

Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for crawl4ai, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.

How do I mitigate CVE-2026-57571 if there is no patch (or I can't update yet)?

Resolve every user-supplied path to its canonical form and reject anything that escapes the intended directory, and run the component under an account that has no read or write access outside the directory it legitimately serves.

Is CVE-2026-57571 actively exploited in the wild?

No public exploit code has been indexed for CVE-2026-57571 yet. This does not mean the vulnerability cannot be exploited — absence of public exploits does not imply safety. Apply the recommended fix and use O3 Security to monitor your exposure.

What is the EPSS score for CVE-2026-57571?

CVE-2026-57571 has an EPSS (Exploit Prediction Scoring System) score of 0.8%, placing it in the 57th percentile of all CVEs. EPSS is maintained by FIRST.org and estimates the probability that a vulnerability will be exploited in the wild within the next 30 days. This score indicates relatively lower exploitation probability, though the CVSS severity should still guide your patching priority.

What type of vulnerability is CVE-2026-57571?

CVE-2026-57571 is classified as Path Traversal (CWE-22), CWE-59 (CWE-59). These weakness types describe the underlying flaw category, which helps determine the potential impact and the right class of mitigation. This is a high-impact weakness class that often enables remote code execution or data exposure.

When was CVE-2026-57571 published, and has it been updated?

CVE-2026-57571 was published on July 6, 2026 and was last updated on October 28, 2026. Advisory data evolves as severity scores, affected ranges, and exploit intelligence are revised — always check the latest version of the advisory before acting.

🐍

🐍 PyPI

Not in CISA KEV

CRITICAL severity

CVE-2026-57571 — crawl4ai

CRITICALFix: unclecode/crawl4ai@60886d1

CVE-2026-57571 is a critical-severity (CVSS 9.6) Path Traversal vulnerability in crawl4ai. A fix is available for crawl4ai — see the affected versions and patch details below.

Crawl4AI arbitrary file write via download filename path traversal

Also known asGHSA-2jq4-q6vv-4cp3PYSEC-2026-2138

Published

Jul 6, 2026

Updated

Oct 28, 2026

Affected

1 pkg

Patched

1 / 1

Exploits

None indexed

Exploitation data as of Oct 28, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

Exploitation Status

No confirmed exploitation observed yet

A successful exploit gives an attacker total control of the affected component, not partial access.
CISA’s own triage has not observed active exploitation or public proof-of-concept code for this CVE as of its last assessment.

Exploitation and automatability from CISA’s SSVC triage for CVE-2026-57571.

EPSS Exploitation Probability

via FIRST.org ↗

0.8%probability of exploitation in next 30 days

Lower Risk0.00%

Lower risk than most CVEs57th percentile — riskier than 57% of all scored CVEsHighest risk

Probability of exploitation in the next 30 days, from FIRST.org EPSS.

How urgent is this, really

CVE-2026-57571 by exploitation likelihood (EPSS) against impact (CVSS). Outside the shaded patch-first corner.

Where this sits among everything scored

Of 396,966 CVEs with a current EPSS score, this one falls in the < 10% band (highlighted). Counts from FIRST.org, log-scaled.

Real-World Exposure

1 pkg affected

🐍crawl4ai

Real-time download stats are indexed for npm and PyPI packages. This vulnerability affects PyPI packages — download data is not available via public APIs for these ecosystems.

Description

Summary

When the crawler saves a downloaded file, the destination filename was taken from attacker-influenced input and joined to the downloads directory with no confinement. A filename containing an absolute path (e.g. /etc/cron.d/evil) or ../ traversal escaped the downloads directory, giving an arbitrary file write with attacker-controlled contents. Because the written bytes are attacker-controlled, this escalates to remote code execution (overwriting a shell rc-file, ~/.ssh/authorized_keys, a cron entry, or a Python module on the import path).

Affected paths

Two download sinks in crawl4ai/async_crawler_strategy.py:

HTTP crawler (AsyncHTTPCrawlerStrategy): the filename is parsed from the response Content-Disposition header by _extract_filename() and written via aiofiles.open(filepath, 'wb'). Reachable directly via the SDK, and via the unauthenticated Docker /crawl endpoint when an HTTPCrawlerConfig is supplied.
Browser crawler (AsyncPlaywrightCrawlerStrategy): the download's suggested_filename (controllable by the visited page) is joined to downloads_path and written via download.save_as().

The HTTP-strategy sink is reachable pre-auth on the default Docker deployment; both are reachable for SDK users simply by crawling an attacker-controlled URL. The default Playwright crawl path that does not trigger a download is unaffected.

Impact

Arbitrary file write with attacker-controlled content as the user running the crawler, escalating to remote code execution.

Fix

Both sinks now resolve the destination through a single hardened helper (_safe_download_filepath) that reduces the attacker-influenced name to a bare basename (dropping absolute paths and .. components) and re-checks, via realpath, that the resolved path stays inside the downloads root (defeating symlink/TOCTOU escapes). A traversal attempt is rejected; normal downloads are unchanged.

Workarounds

Upgrade to the patched version (0.9.0).
Run the crawler as an unprivileged user with a dedicated, isolated downloads directory on a volume with no sensitive paths writable.
Enable authentication (CRAWL4AI_API_TOKEN) on the Docker server.

Credits

Y4tacker - reported the Content-Disposition path traversal in the HTTP crawler with a clear PoC and a basename + realpath-containment fix recommendation.

Affected Packages

1 total 1 fixed

Ecosystem	Package	Vulnerable range	Fix
🐍PyPI	`crawl4ai`	all versions	0.9.0`pip install --upgrade 'crawl4ai==0.9.0'`

Affected Products

1 product · 1 configurations

Application

crawl4aikidocode

< 0.9.0

range

Detection & mitigation playbook

Open-source dependency

Detect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for crawl4ai, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update crawl4ai to 0.9.0 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-57571 is resolved across your whole dependency graph.
Workarounds
Resolve every user-supplied path to its canonical form and reject anything that escapes the intended directory, and run the component under an account that has no read or write access outside the directory it legitimately serves.

Frequently Asked Questions

### Summary When the crawler saves a downloaded file, the destination filename was taken from attacker-influenced input and joined to the downloads directory with no confinement. A filename containing an absolute path (e.g. `/etc/cron.d/evil`) or `../` traversal escaped the downloads directory, giving an arbitrary file write with attacker-controlled contents. Because the written bytes are attacker-controlled, this escalates to remote code execution (overwriting a shell rc-file, `~/.ssh/authorized_keys`, a cron entry, or a Python module on the import path). ### Affected paths Two download si