Vendor_Releases

Adobe - Security bulletins and technical briefs that provide information to customers.
AIX - Security and other patches for AIX. Note that this is an FTP site.
AIX Patches - Fixdist - You need the "fixdist" program to install AIX patches.
Apache Web Server - Advisories and patches.
Cisco - Patches and advisories for Cisco products
Citrix - Security bulletins and hotfixes for Citrix products
Compaq - Patches and advisories for most Compaq products.
Debian: Security Information - Details of current and archive security advisories. Includes mailing list and a security FAQ.
FreeBSD - Advisories, mailing lists, tips, tricks, guidelines, links.
FreeBSD Patches FTP Site - Security advisories and patches.
HP: IT Resource Center - Americas/Asia-Pacific site offering online support. Includes knowledge base, patches, drivers and security mailing lists.
HP: Tru64 Unix - Security advisories and associated patches.
HP-UX Patch Additional Information - Patch Security Matrix, list of obsolete patches, patch checksums.
KDE - Only if you've built KDE yourself; otherwise probably available from your linux distribution vendor's patches directory. Note this is an FTP site.
Microsoft - Download security updates, service packs, and anti-spyware tools for Windows.
Microsoft Security - Microsoft-product-related security headlines and bulletins.
NetBSD - Advisories, patches, links.
Netscape - Security alerts for netscape client and server software.
OpenBSD Release Errata - Advisories and patches.
OpenBSD Security - Advisories and information.
Oracle - Patches and other security information.
Red Hat Linux Errata - Security advisories and updates (patches) for all supported versions.
Red Hat Linux Security Resource Center - Alerts, whitepapers, articles, presentations, and tools.
SCO - Security information for Caldera OpenLinux, OpenServer, OpenUnix, and UnixWare.
SCO Unix System Security Enhancement Area - Advisories and patches. Note this is an FTP site.
SGI: IRIX - Security advisories and patch downloads. Includes mailing list.
Sun Microsystems - Security and recommended patches for Solaris: patch clusters and individual patches.
SuSE Linux - Patches directories for all supported versions, plus a security announcements list (English).