FreeBSD vfs_mount.c buffer overflow

freebsd-vfsmount-bo (45143) The risk level is classified as HighHigh Risk


FreeBSD is vulnerable to a stack-based buffer overflow, caused by improper bounds checking by the vfs_mount.c file in the kernel. If vfs.usermount is enabled, a local attacker could send a specially-crafted mount or nmount system call to overflow a buffer and execute arbitrary code on the system with kernel level privileges.


Base Score: 6.9
  Access Vector: Local
  Access Complexity: Medium
  Authentication: None
  Confidentiality Impact: Complete
  Integrity Impact: Complete
  Availability Impact: Complete
Temporal Score: 5.7
  Exploitability: Functional
  Remediation Level: Official-Fix
  Report Confidence: Confirmed


Gain Privileges


Refer to FreeBSD-SA-08:08.nmount for patch, upgrade or suggested workaround information. See References.


  • FreeBSD Web site: The FreeBSD Project.
  • FreeBSD-SA-08:08.nmount: nmount(2) local arbitrary code execution.
  • BID-31002: FreeBSD 'mount(2)' and 'nmount(2)' Multiple Stack Buffer Overflow Vulnerabilities
  • CVE-2008-3531: Stack-based buffer overflow in sys/kern/vfs_mount.c in the kernel in FreeBSD 7.0 and 7.1, when vfs.usermount is enabled, allows local users to gain privileges via a crafted (1) mount or (2) nmount system call, related to copying of user defined data in certain error conditions.
  • OSVDB ID: 48467: FreeBSD Kernel sys/kern/vfs_mount.c User Data Handling Local Overflow
  • SECTRACK ID: 1020816: FreeBSD nmount(2) Bug Lets Local Users Gain Elevated Privileges

Platforms Affected:

  • FreeBSD FreeBSD 7.0


Sep 03, 2008

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