smtpd/lka_filter.c in OpenSMTPD before 6.8.0p1, in certain configurations, allows remote attackers to cause a denial of service (NULL pointer dereference and daemon crash) via a crafted pattern of client activity, because the filter state machine does not properly maintain the I/O channel between the SMTP engine and the filters layer.
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 |
|---|---|---|---|
| Opensmtpd | Opensmtpd | * | 6.8.0 (excluding) |
| Opensmtpd | Opensmtpd | 6.8.0 (including) | 6.8.0 (including) |
| Opensmtpd | Opensmtpd | 6.8.0-patch1-rc1 (including) | 6.8.0-patch1-rc1 (including) |