Description
In ProFTPD 1.3.7, it is possible to corrupt the memory pool by interrupting the data transfer channel. This triggers a use-after-free in alloc_pool in pool.c, and possible remote code execution.
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 | 1.3.6c-2 | — |
| Debian 13 | proftpd-dfsg | 1.3.6c-2 | — |
| Debian 12 | proftpd-dfsg | 1.3.6c-2 | — |
| Debian 10 | proftpd-dfsg | 1.3.6-4+deb10u4 | DSA-4635-1 |
| Debian 9 | proftpd-dfsg | 1.3.5b-4+deb9u4 | DSA-4635-1 |
Show 1 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Debian 8 | proftpd-dfsg | 1.3.5e+r1.3.5-2+deb8u6 | DLA-2115-2, DLA-2115-1 |
Ubuntu
Security tracker ↗| 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 |
|---|---|---|---|
| SUSE Package Hub 15 SP1 | proftpd | 1.3.6c-bp151.4.9.1 | openSUSE-SU-2020:0273-1 |
| SUSE Package Hub 15 | proftpd | 1.3.6c-bp151.4.9.1 | openSUSE-SU-2020:0273-1 |
openSUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| openSUSE Tumbleweed | proftpd | 1.3.6e-1.10 | openSUSE-SU-2024:11196-1 |
| openSUSE Leap 15.1 | proftpd | 1.3.6c-bp151.4.9.1 | openSUSE-SU-2020:0273-1 |
Public exploits
Exploit or proof-of-concept code for this vulnerability is publicly available, which lowers the bar for attackers. Treat it as a reason to patch sooner.
Third-party code, not reviewed by us. Public PoCs are sometimes fake or contain malware. Read the code first and run it only in an isolated lab, against systems you are authorised to test.
GitHub 1 repository
-
dukptkey/CVE-2020-9273 ★ 14 · Nov 5, 2020
Analysis and exploitation of an use-after-free in ProFTPd
Sources: PoC-in-GitHub, Metasploit Framework, Exploit-DB — updated daily. Only links are listed; no exploit code is hosted here.
Advisories 7
- DSA-4635-1 proftpd-dfsg - security update Debian Security (DSA / DLA) · Mar 9, 2026
- DLA-2115-1 proftpd-dfsg - security update Debian Security (DSA / DLA) · Mar 9, 2026
- DLA-2115-2 proftpd-dfsg - regression update Debian Security (DSA / DLA) · Mar 9, 2026
- openSUSE-SU-2020:0273-1 Security update for proftpd SUSE / openSUSE Security Updates · Feb 4, 2026
- openSUSE-SU-2024:11196-1 proftpd-1.3.6e-1.10 on GA media SUSE / openSUSE Security Updates · Feb 4, 2026
- ICSA-21-222-07 Siemens SIMATIC CP (Update A) CISA ICS & IT advisories · Jun 14, 2022
- SSA-679335 SSA-679335: Multiple Vulnerabilities in Embedded FTP Server of SIMATIC CP Modules Siemens ProductCERT · Jun 14, 2022
References
- https://github.com/proftpd/proftpd/blob/master/RELEASE_NOTES
- https://github.com/proftpd/proftpd/issues/903
- [debian-lts-announce] 20200221 [SECURITY] [DLA 2115-1] proftpd-dfsg security update mailing-list
- DSA-4635 vendor-advisory
- FEDORA-2020-76c707cff0 vendor-advisory
- FEDORA-2020-876b1f664e vendor-advisory
- openSUSE-SU-2020:0273 vendor-advisory
- [debian-lts-announce] 20200302 [SECURITY] [DLA 2115-2] proftpd-dfsg regression update mailing-list
- GLSA-202003-35 vendor-advisory
- https://cert-portal.siemens.com/productcert/pdf/ssa-679335.pdf
- [oss-security] 20210824 Possible memory leak on getspnam / getspnam_r mailing-list
- [oss-security] 20210906 Re: Possible memory leak on getspnam / getspnam_r mailing-list