When Eclipse Mosquitto version 1.0 to 1.5.5 (inclusive) is configured to use a password file for authentication, any malformed data in the password file will be treated as valid. This typically means that the malformed data becomes a username and no password. If this occurs, clients can circumvent authentication and get access to the broker by using the malformed username. In particular, a blank line will be treated as a valid empty username. Other security measures are unaffected. Users who have only used the mosquitto_passwd utility to create and modify their password files are unaffected by this vulnerability.
The product does not properly anticipate or handle exceptional conditions that rarely occur during normal operation of the product.
| Name | Vendor | Start Version | End Version |
|---|---|---|---|
| Mosquitto | Eclipse | 1.0 (including) | 1.5.5 (including) |
| Mosquitto | Ubuntu | bionic | * |
| Mosquitto | Ubuntu | cosmic | * |
| Mosquitto | Ubuntu | upstream | * |
| Mosquitto | Ubuntu | xenial | * |