- Full Tier-1 support for single and multiprocessor AMD Athlon64 and Opteron systems.
- Dynamically linked root partition for a smaller installation footprint and better integration with the Name Service Switch subsystem.
- New and improved driver support for IDE, SATA, and 802.11a/b/g devices, and significantly better integration with the ACPI power management subsystem.
- Client support for the Network File System version 4 protocol.
- Experimental first-stage support for multithreaded filtering and forwarding of IP traffic. This also provides the foundation for a fully multi-threaded network stack in the next release of FreeBSD.
- In-box support for the latest Gnome 2.4 and KDE 3.1 desktops.
A single-byte buffer overflow in realpath(3) was fixed. Although the fix was committed prior to FreeBSD 5.1-RELEASE (and thus 5.1-RELEASE was not affected), it was not noted in the release documentation. See security advisory FreeBSD-SA-03:08.
A bug that could allow the kernel to attempt delivery of invalid signals has been fixed. The bug could have led to a kernel panic or, under some circumstances, unauthorized modification of kernel memory. For more information, see security advisory FreeBSD-SA-03:09.
A bug in the iBCS2 emulation module, which could result in disclosing the contents of kernel memory, has been fixed. This module is not enabled in FreeBSD by default. For more information, see security advisory FreeBSD-SA-03:10.
A buffer management bug in OpenSSH, which could potentially cause a crash, has been fixed. More information can be found in security advisory FreeBSD-SA-03:12.
A buffer overflow in sendmail has been fixed. More information can be found in security advisory FreeBSD-SA-03:13.
A bug that could allow the kernel to cause resource starvation which eventually results in a system panic in the ARP cache code has been fixed. More information can be found in security advisory FreeBSD-SA-03:14.
Several errors in the OpenSSH PAM challenge/response authentication subsystem have been fixed. The impacts of these bugs vary; details can be found in security advisory FreeBSD-SA-03:15.
A bug in procfs(5) and linprocfs(5), which could result in disclosing the contents of kernel memory, has been fixed. More information can be found in security advisory FreeBSD-SA-03:17.
Four separate security flaws in OpenSSL, which could allow a remote attacker to crash an OpenSSL-using application or to execute arbitrary code with the privileges of the application, have been fixed. More information can be found in security advisory FreeBSD-SA-03:18.
A potential denial of service in BIND has been fixed. For more information, see security advisory FreeBSD-SA-03:19.