ComSndFTP FTP Server version 1.3.7 Beta contains a format string vulnerability in its handling of the USER command. By sending a specially crafted username containing format specifiers, a remote attacker can overwrite a hardcoded function pointer in memory (specifically WSACleanup from Ws2_32.dll). This allows the attacker to redirect execution flow and bypass DEP protections using a ROP chain, ultimately leading to arbitrary code execution. The vulnerability is exploitable without authentication and affects default configurations.
https://www.vulncheck.com/advisories/comsndftp-user-format-string-rce
https://www.exploit-db.com/exploits/19177
https://www.exploit-db.com/exploits/19024
https://web.archive.org/web/20120317214524/http://ftp.comsnd.com/
Published: 2025-08-13
Updated: 2025-08-14
Base Score: 6.8
Vector: CVSS2#AV:N/AC:M/Au:N/C:P/I:P/A:P
Severity: Medium
Base Score: 8.8
Vector: CVSS:3.0/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
Severity: High
Base Score: 9.3
Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N
Severity: Critical
EPSS: 0.00406