Description
ProFTPD through 1.3.9e and 1.3.10rc1 through 1.3.10rc4 contains a link-following vulnerability in mod_copy that allows authenticated FTP users to bypass Limit WRITE restrictions via symlinks. Attackers can place a symlink in a writable directory and use SITE COPY or SITE CPTO to overwrite files in write-denied locations.
Affected products
| Vendor | Product | Affected | Fixed |
|---|---|---|---|
| ProFTPD Project | ProFTPD | ≤ 1.3.9e, 1.3.10rc1 – < 1.3.10rc5 | 1.3.10rc5 |
Fixed in Linux distributions
Distributions backport fixes, so the version that fixes this vulnerability differs per release — upgrade to at least the version shown. From the distributions' security trackers and advisories.
Debian
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Debian 14 | proftpd-dfsg | 1.3.9e~dfsg-3 | — |
| Debian 13 | proftpd-dfsg | No fix yet | — |
| Debian 12 | proftpd-dfsg | No fix yet | — |
Ubuntu
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu 26.10 | proftpd-dfsg | No fix yet | — |
| Ubuntu 26.04 LTS | proftpd-dfsg | No fix yet | — |
| Ubuntu 24.04 LTS | proftpd-dfsg | No fix yet | — |
| Ubuntu 22.04 LTS | proftpd-dfsg | No fix yet | — |
| Ubuntu 20.04 LTS | proftpd-dfsg | No fix yet | — |
Show 2 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu 18.04 LTS | proftpd-dfsg | No fix yet | — |
| Ubuntu 16.04 LTS | proftpd-dfsg | No fix yet | — |
Alpine
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Alpine v3.24 | proftpd | 1.3.9e-r0 | — |
| Alpine v3.23 | proftpd | 1.3.9e-r0 | — |
Advisories 1
- WID-SEC-2026-4259 ProFTPD: Mehrere Schwachstellen ermöglichen Manipulation von Dateien BSI CERT-Bund (WID) · Nov 10, 2026
References
- https://github.com/proftpd/proftpd/issues/2374 issue-tracking
- https://github.com/proftpd/proftpd/commit/c41691f8981f98081fcb8a535c3c21b06a3f04af patch
- https://github.com/proftpd/proftpd/blob/v1.3.9e/contrib/mod_copy.c#L620 technical-description
- ProFTPD v1.3.10rc5 Release Notes release-notes
- https://abraxaslabs.tech/research/proftpd-site-copy-dest-follow third-party-advisory
- https://github.com/proftpd/proftpd product
- VulnCheck Advisory: ProFTPD through 1.3.9e and 1.3.10rc4 mod_copy Symlink Following Write Bypass third-party-advisory