CVE-2021-35250
Published: April 11, 2026
Official Description
A researcher reported a Directory Transversal Vulnerability in Serv-U 15.3. This may allow access to files relating to the Serv-U installation and server files. This issue has been resolved in Serv-U 15.3 Hotfix 1.
Risk Analysis
A Directory Traversal Vulnerability in Serv-U 15.3 allows access to files related to the Serv-U installation and server files. This could lead to sensitive information disclosure or further system compromise. The inclusion in CISA's KEV catalog indicates confirmed exploitation.
This vulnerability is being actively exploited in the wild. It allows access to sensitive files on the server.
Upgrade Serv-U to version 15.3 Hotfix 1 or later to resolve this directory traversal vulnerability. Regularly review and restrict file system permissions.
Technical Analysis
CVE-2021-35250 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-2021-35250 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
Quick Facts
Recommended Actions
- →Apply vendor patches immediately
- →Monitor CVE-2021-35250 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