CVE-2026-35025

ProFTPD through 1.3.9b and 1.3.10rc2 contains an access control bypass vulnerability that allows authenticated FTP users to circumvent Directory ACL restrictions by prefixing paths with /proc/self/root in the RNFR command handler. Attackers can exploit the unresolved symlink components in dir_canonical_path() to cause dir_check() to perform lexical path comparisons that match no configured Directory block, enabling rename operations on files in DenyAll-protected directories and subsequent retrieval of those files. Mitigation: Sessions configured with DefaultRoot (chroot) are not affected, as chroot changes the directory to which /proc/self/root resolves.

• http://www.proftpd.org/
• https://github.com/proftpd/proftpd/issues/2170
• https://www.vulncheck.com/advisories/proftpd-acl-bypass-via-proc-self-root-path-prefix-in-rnfr