Arbitrary File Write Vulnerability in crawl4ai by UncleCode
CVE-2026-91940

8.7HIGH

Key Information:

Vendor

Unclecode

Status
Crawl4ai
Vendor
CVE Published:
15 September 2026

Badges

👾 Exploit Exists🟡 Public PoC

What is CVE-2026-91940?

The crawl4ai tool prior to version 0.9.3 has a vulnerability where the PDFContentScrapingStrategy's _filter_untrusted_fields function fails to properly validate untrusted configuration fields. This flaw enables attackers to submit specially crafted configuration bodies, potentially containing malicious image_save_dir paths. Consequently, this allows unauthorized writing of attacker-controlled data into any directory that is accessible to the service account, posing significant risks to data security and system integrity.

Affected Version(s)

crawl4ai 0.9.0 < 0.9.3

crawl4ai 0.9.3

Exploit Proof of Concept (PoC)

PoC code is written by security researchers to demonstrate the vulnerability can be exploited. PoC code is also a key component for weaponization which could lead to ransomware.

CVE-2026-91940-crawl4ai-Arbitrary-File-Write
Created by BiiTts

References

https://github.com/unclecode/crawl4ai/security/advisories...
vendor-advisory
https://www.vulncheck.com/advisories/crawl4ai-before-0.9....
third-party-advisory

CVSS V4

Score:
8.7
Severity:
HIGH
Confidentiality:
None
Integrity:
High
Availability:
None
Attack Vector:
Network
Attack Complexity:
Low
Attack Required:
None
Privileges Required:
Undefined
User Interaction:
None

Timeline

  • 🟡

    Public PoC available

  • 👾

    Exploit known to exist

  • Vulnerability published

  • Vulnerability Reserved

Credit

manus-use
.