Description
An issue was discovered in tls_verify_crl in ProFTPD through 1.3.6b. Failure to check for the appropriate field of a CRL entry (checking twice for subject, rather than once for subject and once for issuer) prevents some valid CRLs from being taken into account, and can allow clients whose certificates have been revoked to proceed with a connection to the server.
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 | 1.3.6b-2 | — |
| Debian 13 | proftpd-dfsg | 1.3.6b-2 | — |
| Debian 12 | proftpd-dfsg | 1.3.6b-2 | — |
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 25.10 | proftpd-dfsg | No fix yet | — |
| Ubuntu 24.04 LTS | proftpd-dfsg | No fix yet | — |
| Ubuntu 22.04 LTS | proftpd-dfsg | No fix yet | — |
Show 3 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu 20.04 LTS | proftpd-dfsg | No fix yet | — |
| 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 | 1.3.6b-bp151.4.6.2 | openSUSE-SU-2020:0031-1 |
| SUSE Package Hub 15 | proftpd | 1.3.6b-bp151.4.6.2 | openSUSE-SU-2020:0031-1 |
openSUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| openSUSE Leap 15.1 | proftpd | 1.3.6b-bp151.4.6.2 | openSUSE-SU-2020:0031-1 |
Advisories 1
- openSUSE-SU-2020:0031-1 Security update for proftpd SUSE / openSUSE Security Updates · Feb 4, 2026
References
- https://github.com/proftpd/proftpd/issues/859
- FEDORA-2019-65a983b8b6 vendor-advisory
- FEDORA-2019-bfacf1e958 vendor-advisory
- openSUSE-SU-2020:0031 vendor-advisory