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.
| Software | From | Fixed in |
|---|---|---|
| freebsd / freebsd | 4.1 | 4.1.x |
| freebsd / freebsd | 3.0 | 3.0.x |
| freebsd / freebsd | 4.0 | 4.0.x |
| freebsd / freebsd | 4.1.1 | 4.1.1.x |
| freebsd / freebsd | 2.0 | 2.0.x |