Apache httpd 1.3.37, 2.0.59, and 2.2.4 with the Prefork MPM module, allows local users to cause a denial of service by modifying the worker_score and process_score arrays to reference an arbitrary process ID, which is sent a SIGUSR1 signal from the master process, aka SIGUSR1 killer.
| Name | Vendor | Start Version | End Version |
|---|---|---|---|
| Http_server | Apache | 1.3.0 (including) | 1.3.39 (excluding) |
| Http_server | Apache | 2.0.0 (including) | 2.0.61 (excluding) |
| Http_server | Apache | 2.2.0 (including) | 2.2.6 (excluding) |