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7.2

FreeBSD mount_union lets local users become root

CVE-1999-0963 · published 26 years ago
Summary

On systems running FreeBSD, the mount_union command can be tricked by a local user using a specially crafted shortcut (symlink) to gain full administrative rights. This means an attacker with a regular account could take control of the entire system. Apply the available operating system update or disable the mount_union feature until it is patched.

What to do

The CVE record does not list a fixed version. Check the vendor's site or the advisory links below - a fix may already be released.

Affected software
VendorProductAffected versions
freebsd freebsd 2.2
cpe:2.3:o:freebsd:freebsd:2.2:*:*:*:*:*:*:*
Original advisory text
FreeBSD mount_union command allows local users to gain root privileges via a symlink attack.
FreeBSD mount_union command allows local users to gain root privileges via a symlink attack.
References
Fix within
Internet-facing 14 days
Internal At next upgrade
  • Not known to be exploited
  • Needs hands-on effort to exploit (estimated)
  • Gives an attacker full control (estimated)
Severity
7.2 High
Exploitation
<1% chance of attack within 30 days
Timeline
Published1 Dec 1999
Updated4 Nov 2026
First seen29 Sep 2026
Sources
CVE-1999-0963 · NVD
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