CVE-2009-1895: Canonical Ubuntu Linux

High severity, CVSS 7.2. EPSS: 0.4% chance of exploitation in the next 30 days.

The personality subsystem in the Linux kernel before 2.6.31-rc3 has a PER_CLEAR_ON_SETID setting that does not clear the ADDR_COMPAT_LAYOUT and MMAP_PAGE_ZERO flags when executing a setuid or setgid program, which makes it easier for local users to leverage the details of memory usage to (1) conduct NULL pointer dereference attacks, (2) bypass the mmap_min_addr protection mechanism, or (3) defeat address space layout randomization (ASLR).

Affected products

• Canonical Ubuntu Linux: version 6.06 only; version 8.04 only; version 8.10 only; version 9.04 only
• Debian Debian Linux: version 4.0 only; version 5.0 only
• Linux Linux Kernel: up to and including 2.6.31; version 2.6.31 only

Published 2009-07-16. Last modified 2026-06-16.