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).
Fixed in Linux distributions
Distributions backport fixes, so the version that fixes this vulnerability differs per release — upgrade to at least the version shown. From the distributions' security trackers and advisories.
Debian
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Debian 5.0 | linux-2.6 | 2.6.26-17lenny1 | DSA-1845-1 |
| Debian 4.0 | linux-2.6.24 | 2.6.24-6~etchnhalf.8etch2 | DSA-1844-1 |
Red Hat
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| RHEL 5 | kernel +12 | 2.6.18-128.4.1.el5 | RHSA-2009:1193 |
| RHEL 4 | kernel +10 | 2.6.9-89.0.11.EL | RHSA-2009:1438 |
| RHEL 3 | kernel +8 | 2.4.21-63.EL | RHSA-2009:1550 |
Show 3 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| RHEL 5.3 EUS | kernel +12 | 2.6.18-128.4.1.el5 | RHSA-2009:1193 |
| RHEL 5.2 EUS | kernel +11 | 2.6.18-92.1.35.el5 | RHSA-2010:0079 |
| Red Hat MRG 1 | kernel-rt +9 | 2.6.24.7-137.el5rt | RHSA-2009:1540 |
Advisories 7
- RHSA-2010:0079 Red Hat Security Advisory: kernel security and bug fix update Red Hat Security Advisories (RHSA) · Jun 29, 2026
- RHSA-2009:1540 Red Hat Security Advisory: kernel-rt security, bug fix, and enhancement update Red Hat Security Advisories (RHSA) · Jun 29, 2026
- RHSA-2009:1550 Red Hat Security Advisory: kernel security and bug fix update Red Hat Security Advisories (RHSA) · Jun 28, 2026
- RHSA-2009:1193 Red Hat Security Advisory: kernel security and bug fix update Red Hat Security Advisories (RHSA) · Jun 28, 2026
- RHSA-2009:1438 Red Hat Security Advisory: kernel security and bug fix update Red Hat Security Advisories (RHSA) · Jun 26, 2026
- DSA-1844-1 linux-2.6.24 - several vulnerabilities Debian Security (DSA / DLA) · Mar 9, 2026
- DSA-1845-1 linux-2.6 - several vulnerabilities Debian Security (DSA / DLA) · Mar 9, 2026
References
- 20100625 VMSA-2010-0010 ESX 3.5 third party update for Service Console kernel mailing-list
- http://wiki.rpath.com/Advisories:rPSA-2009-0111
- 36131 third-party-advisory
- 55807 vdb-entry
- ADV-2009-1866 vdb-entry
- RHSA-2009:1540 vendor-advisory
- 37471 third-party-advisory
- 36759 third-party-advisory
- FEDORA-2009-8144 vendor-advisory
- DSA-1844 vendor-advisory
- USN-807-1 vendor-advisory
- http://www.vmware.com/security/advisories/VMSA-2009-0016.html
- RHSA-2009:1193 vendor-advisory
- http://git.kernel.org/?p=linux/kernel/git/torvalds/linux-2.6.git%3Ba=commit%3Bh=f9fabcb58a6d26d6efde842d1703ac7cfa9427b6
- oval:org.mitre.oval:def:7826 vdb-entry signature
- 35647 vdb-entry
- FEDORA-2009-8264 vendor-advisory
- 20090724 rPSA-2009-0111-1 kernel mailing-list
- http://blog.cr0.org/2009/06/bypassing-linux-null-pointer.html
- MDVSA-2011:051 vendor-advisory
- 20091120 VMSA-2009-0016 VMware vCenter and ESX update release and vMA patch release address multiple security issue in third party components mailing-list
- 36051 third-party-advisory
- oval:org.mitre.oval:def:11768 vdb-entry signature
- 36045 third-party-advisory
- 36116 third-party-advisory
- RHSA-2009:1550 vendor-advisory
- http://patchwork.kernel.org/patch/32598/
- http://www.kernel.org/pub/linux/kernel/v2.6/testing/ChangeLog-2.6.31-rc3
- 35801 third-party-advisory
- 36054 third-party-advisory
- https://bugs.launchpad.net/bugs/cve/2009-1895
- DSA-1845 vendor-advisory
- oval:org.mitre.oval:def:9453 vdb-entry signature
- RHSA-2009:1438 vendor-advisory
- ADV-2009-3316 vdb-entry