Description
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.
Severity (CVSS)
| Base score | 8.6 |
|---|---|
| Severity | High |
| Version | CVSS 4.0 |
| Vector | CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N |
| Provided by | CNA |
Weaknesses
- CWE-59 — Improper Link Resolution Before File Access ('Link Following')
Affected products
| Vendor | Product | Versions |
|---|---|---|
| ProFTPD Project | ProFTPD | 0 to <=1.3.9b; 0 to <=1.3.10rc2 |
References
- https://github.com/proftpd/proftpd/issues/2170 (technical-description)
- http://www.proftpd.org/ (product)
- https://www.vulncheck.com/advisories/proftpd-acl-bypass-via-proc-self-root-path-prefix-in-rnfr (third-party-advisory)
Generated from the official CVE List on 25 Jun 2026 10:14 UTC.