CVE-2024-4040
Published: April 24, 2024
Official Description
CrushFTP contains an unspecified sandbox escape vulnerability that allows a remote attacker to escape the CrushFTP virtual file system (VFS).
CISA KEV Advisory
CrushFTP VFS Sandbox Escape Vulnerability
CrushFTP contains an unspecified sandbox escape vulnerability that allows a remote attacker to escape the CrushFTP virtual file system (VFS).
Apply mitigations per vendor instructions or discontinue use of the product if mitigations are unavailable.
Risk Analysis
CrushFTP contains an unspecified sandbox escape vulnerability, allowing a remote attacker to break out of the virtual file system (VFS). This high-severity flaw, with its high EPSS score and confirmed exploitation, poses a significant risk. Successful exploitation could lead to unauthorized access to the underlying operating system.
This vulnerability is actively exploited in the wild and is listed in CISA's KEV catalog, confirming its use by threat actors. The nature of the flaw suggests it is remotely exploitable, allowing an attacker to escape the VFS.
CrushFTP users should apply the latest security patches to address this sandbox escape vulnerability. Implementing strict access controls and regularly reviewing system logs for unusual activity are also recommended.
Technical Analysis
CVE-2024-4040 requires local access, meaning attackers must already have a foothold on the target system.
Exploitation requires some privileges, which limits the exposure to scenarios where an attacker has already gained initial access.
CISA has added CVE-2024-4040 to the Known Exploited Vulnerabilities (KEV) catalog, confirming active exploitation in the wild. U.S. federal agencies are required to patch this within the mandated timeframe, and all organizations should treat remediation as urgent.
Exploit & PoC Resources
News & Research Mentioning CVE-2024-4040
CrushFTP is a Java-based open source file transfer system. It is offered for multiple operating systems. If you run a CrushFTP instance, you may remember that the software has had some serious vulnerabilities: CVE-2024-4040 (the template-injection flaw that let unauthenticated attackers escape the VFS sandbox and achieve RCE), CVE-2025-31161 (the auth-bypass that handed over the crushadmin account on a silver platter), and the July 2025 zero-day CVE-2025-54309 that was actively exploited in the wild. [xlite_meta score:72 src:SANS ISC xlite_fp:b811a697d8e8ef962ac5b77c1269ff4e79f3e4f271302acd70950196d560ddf7]
All References (2)
Quick Facts
Known Threat Actors
Recommended Actions
- →Apply vendor patches immediately
- →Monitor CVE-2024-4040 in threat intel feeds
- →Review IDS/IPS signatures for exploitation attempts
- !CISA KEV: Federal agencies must patch per BOD 22-01 timeline
- !Active exploitation confirmed — treat as P1