FreeBSD 4.1.1 and earlier, and possibly other BSD-based OSes, uses an insufficient random number generator to generate initial TCP sequence numbers (ISN), which allows remote attackers to spoof TCP connections.
| Name | Vendor | Start Version | End Version |
|---|---|---|---|
| Freebsd | Freebsd | 2.0 | 2.0 |
| Freebsd | Freebsd | 3.0 | 3.0 |
| Freebsd | Freebsd | 4.0 | 4.0 |
| Freebsd | Freebsd | 4.1 | 4.1 |
| Freebsd | Freebsd | 4.1.1 | 4.1.1 |