Open-source LLM Friendly Web Crawler Vulnerability in Crawl4AI
CVE-2026-53753

9.8CRITICAL

Key Information:

Vendor

Unclecode

Status
Crawl4ai
Vendor
CVE Published:
23 June 2026

What is CVE-2026-53753?

Crawl4AI, an open-source LLM-friendly web crawler, prior to version 0.8.7, contains a critical vulnerability in its computed fields feature. The _safe_eval_expression() function employs an AST validator that inadequately restricts attribute access, allowing attributes without an underscore prefix to execute arbitrary code. This enables attackers to escape the intended sandbox environment and execute malicious commands, potentially compromising the integrity of the system. The vulnerability can be exploited without authentication, as JWT is disabled by default, making it accessible through a crafted POST request to /crawl. The issue was resolved in version 0.8.7.

Affected Version(s)

crawl4ai < 0.8.7

References

https://github.com/unclecode/crawl4ai/security/advisories...
x_refsource_CONFIRM

CVSS V3.1

Score:
9.8
Severity:
CRITICAL
Confidentiality:
High
Integrity:
High
Availability:
High
Attack Vector:
Network
Attack Complexity:
Low
Privileges Required:
None
User Interaction:
None
Scope:
Unchanged

Timeline

  • Vulnerability published

  • Vulnerability Reserved

.