Description
ProFTPD before 1.3.9e and 1.3.10rc5 contains an authorization bypass in the mod_sftp copy-file extension handler that skips Limit WRITE checks for new destination files. Authenticated SFTP users can copy any readable file to a new path in write-denied directories, creating files where uploads are forbidden.
Affected products
| Vendor | Product | Affected | Fixed |
|---|---|---|---|
| ProFTPD Project | ProFTPD | < 1.3.9e, 1.3.10rc1 – < 1.3.10rc5 | 1.3.9e |
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-1 | — |
| 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 | — |
SUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| SLES 15 SP7 | proftpd | 1.3.8b-150600.13.18.1 | SUSE-SU-2026:5181-1 |
| SLES 15 SP6 | proftpd | 1.3.8b-150600.13.18.1 | SUSE-SU-2026:5181-1 |
Show 1 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| SLES for SAP 15 SP6 | proftpd | 1.3.8b-150600.13.18.1 | SUSE-SU-2026:5181-1 |
openSUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| openSUSE Tumbleweed | proftpd | 1.3.9e-1.1 | openSUSE-SU-2026:12438-1 |
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 3
- SUSE-SU-2026:5181-1 Security update for proftpd SUSE / openSUSE Security Updates · Nov 11, 2026
- WID-SEC-2026-4259 ProFTPD: Mehrere Schwachstellen ermöglichen Manipulation von Dateien BSI CERT-Bund (WID) · Nov 10, 2026
- openSUSE-SU-2026:12438-1 proftpd-1.3.9e-1.1 on GA media SUSE / openSUSE Security Updates · Nov 6, 2026
References
- https://github.com/proftpd/proftpd/commit/b7d3de4565ae448a510feecd17b41923e44bfe16 patch
- https://github.com/proftpd/proftpd/blob/v1.3.9d/contrib/mod_sftp/fxp.c#L4748 technical-description
- ProFTPD v1.3.9e Release Notes release-notes
- ProFTPD v1.3.10rc5 Release Notes release-notes
- https://abraxaslabs.tech/research/proftpd-sftp-copy-file-write third-party-advisory
- https://github.com/proftpd/proftpd product
- VulnCheck Advisory: ProFTPD before 1.3.9e and 1.3.10rc5 mod_sftp Copy-File Authorization Bypass third-party-advisory