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Arbitrary File Write in Crawl4AI screenshot and PDF endpoints
CVE-2026-56258 affects Crawl4AI versions before 0.8.8. The vulnerability is an arbitrary file write flaw in the screenshot and PDF endpoints involving the output_path parameter. Due to insufficient path validation, symlink following, and a time-of-check-time-of-use (TOCTOU) race condition, an unauthenticated remote attacker can cause the application to write files outside the intended directory. The issue arises when attacker-controlled output_path handling does not safely constrain filesystem targets and can be raced or redirected via symlinks, enabling writes to unintended locations on the host.
What it means and what to do now: patch path, interim mitigations, and the assume-compromise checklist.
What an attacker gets, and what they’ve been doing with it.
Successful exploitation allows unauthenticated remote attackers to write arbitrary files outside the intended output directory with the privileges of the Crawl4AI runtime user. This can result in overwriting or planting files in sensitive locations and may lead to remote code execution if the service account can write to executable paths, startup locations, or cron-related directories. At minimum, the flaw can compromise filesystem integrity and application or host security boundaries.
If you can’t patch tonight, do this now.
If immediate patching is not possible, restrict or disable external exposure of the vulnerable screenshot and PDF endpoints, prevent untrusted users from controlling the output_path parameter, and run Crawl4AI with the minimum filesystem privileges necessary. Additionally, harden the host against symlink abuse, and ensure the runtime user cannot write to executable directories, cron locations, or other sensitive paths until the fixed version is deployed.
Patch, then assume compromise.
Upgrade Crawl4AI to version 0.8.8 or later. The fix should ensure robust path validation for output_path, prevent symlink traversal/following for attacker-influenced file targets, and eliminate the TOCTOU condition in file creation and write operations. Review filesystem write logic in the screenshot and PDF endpoints to ensure writes are constrained to an intended directory using race-safe file handling.
No public exploits tracked yet. Mallory keeps watching.
Products and vendors Mallory has correlated with this vulnerability. Open in Mallory to drill down to specific CPE configurations and version ranges.
3 sources tracked across advisories, community write-ups, and news. New activity surfaces here as Mallory finds it.