An issue was discovered in tls_verify_crl in ProFTPD through 1.3.6b. A dereference of a NULL pointer may occur. This pointer is returned by the OpenSSL sk_X509_REVOKED_value() function when encountering an empty CRL installed by a system administrator. The dereference occurs when validating the certificate of a client connecting to the server in a TLS client/server mutual-authentication setup.
A NULL pointer dereference occurs when the application dereferences a pointer that it expects to be valid, but is NULL, typically causing a crash or exit.
| Name | Vendor | Start Version | End Version |
|---|---|---|---|
| Proftpd | Proftpd | * | 1.3.5e (including) |
| Proftpd | Proftpd | 1.3.6 (including) | 1.3.6 (including) |
| Proftpd | Proftpd | 1.3.6-alpha (including) | 1.3.6-alpha (including) |
| Proftpd | Proftpd | 1.3.6-beta (including) | 1.3.6-beta (including) |
| Proftpd | Proftpd | 1.3.6-rc1 (including) | 1.3.6-rc1 (including) |
| Proftpd | Proftpd | 1.3.6-rc2 (including) | 1.3.6-rc2 (including) |
| Proftpd | Proftpd | 1.3.6-rc3 (including) | 1.3.6-rc3 (including) |
| Proftpd | Proftpd | 1.3.6-rc4 (including) | 1.3.6-rc4 (including) |
| Proftpd-dfsg | Ubuntu | bionic | * |
| Proftpd-dfsg | Ubuntu | disco | * |
| Proftpd-dfsg | Ubuntu | eoan | * |
| Proftpd-dfsg | Ubuntu | groovy | * |
| Proftpd-dfsg | Ubuntu | hirsute | * |
| Proftpd-dfsg | Ubuntu | impish | * |
| Proftpd-dfsg | Ubuntu | kinetic | * |
| Proftpd-dfsg | Ubuntu | lunar | * |
| Proftpd-dfsg | Ubuntu | mantic | * |
| Proftpd-dfsg | Ubuntu | trusty | * |
| Proftpd-dfsg | Ubuntu | xenial | * |