CVE-2009-1895

Severity: high (CVSS 7.2 v2.0)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.4% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2009-07-16 · updated 2026-06-16
Weakness: CWE-16

Description

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: 6.06, 8.04, 8.10, 9.04
Debian Linux: 4.0, 5.0
Linux kernel: through 2.6.31; 2.6.31-rc1, 2.6.31-rc2

References

http://blog.cr0.org/2009/06/bypassing-linux-null-pointer.html
http://git.kernel.org/?p=linux/kernel/git/torvalds/linux-2.6.git%3Ba=commit%3Bh=f9fabcb58a6d26d6efde842d1703ac7cfa9427b6
http://patchwork.kernel.org/patch/32598/
http://secunia.com/advisories/35801
http://secunia.com/advisories/36045
http://secunia.com/advisories/36051
http://secunia.com/advisories/36054
http://secunia.com/advisories/36116
http://secunia.com/advisories/36131
http://secunia.com/advisories/36759
http://secunia.com/advisories/37471
http://wiki.rpath.com/Advisories:rPSA-2009-0111

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