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PatchSiren cyber security CVE debrief

CVE-2026-57571 unclecode CVE debrief

CVE-2026-57571 is a critical vulnerability in Crawl4AI, an open-source LLM-friendly web crawler and scraper. The issue allows for arbitrary file writes due to a filename traversal vulnerability. Prior to version 0.9.0, the crawler saves downloaded files with filenames taken from attacker-influenced input, joined to the downloads directory without confinement. This enables an attacker to write files with controlled contents, potentially leading to remote code execution. The vulnerability is fixed in version 0.9.0.

Vendor
unclecode
Product
crawl4ai
CVSS
CRITICAL 9.6
CISA KEV
Not listed in stored evidence
Original CVE published
2026-07-06
Original CVE updated
2026-07-07
Advisory published
2026-07-06
Advisory updated
2026-07-07

Who should care

Users of Crawl4AI, especially those using versions prior to 0.9.0, should be aware of this vulnerability and take immediate action to update to the patched version. Security teams and administrators responsible for web crawlers and scrapers should also be informed.

Technical summary

The vulnerability in Crawl4AI arises from the way it handles filenames when saving downloaded files. The filename is taken from attacker-influenced input and joined to the downloads directory without proper confinement. This allows an attacker to specify a filename that could result in an arbitrary file write. The issue is exacerbated by the fact that the written bytes are attacker-controlled, potentially leading to remote code execution. The vulnerability is characterized by the following: CVSS Score: 9.6, CVSS Severity: CRITICAL, AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:H.

Defensive priority

High

Recommended defensive actions

  • Update Crawl4AI to version 0.9.0 or later
  • Review and restrict write access to the downloads directory
  • Monitor for suspicious file writes and system changes
  • Implement additional security measures such as SELinux or AppArmor to confine the crawler's file system access
  • Perform a thorough review of system logs to detect potential exploitation attempts
  • Verify that all Crawl4AI instances are updated and compliant with the new version
  • Conduct a vulnerability scan to identify any exposed systems

Evidence notes

The CVE record was published on 2026-07-06T21:16:57.907Z and was last modified on 2026-07-07T19:07:22.790Z. The NVD entry is currently Analyzed. The vulnerability is described in the CVE record and additional details are provided in the GitHub security advisory.

Sources and references

Verified primary and authoritative sources

  • CVE-2026-57571 CVE Program record

    Publisher, destination, and source semantics verified

    URL: https://www.cve.org/CVERecord?id=CVE-2026-57571

    CVE Program - Official CVE Program record with source-provided CVE metadata.

  • CVE-2026-57571 NVD vulnerability detail

    Publisher, destination, and source semantics verified

    URL: https://nvd.nist.gov/vuln/detail/CVE-2026-57571

    NIST National Vulnerability Database - Official NIST NVD detail page and source-specific vulnerability assessment.

Supplemental references

Methodology and review provenance

AI-assisted synthesis based on stored public vulnerability evidence. System validation, approval state, and publication status do not by themselves establish human review of this revision. PatchSiren helps prioritize defensive review and does not prove exposure or remediation on any system.