The change_process_uid function in os-posix.c in Qemu 0.14.0 and earlier does not properly drop group privileges when the -runas option is used, which allows local guest users to access restricted files on the host.

References

• https://nvd.nist.gov/vuln/detail/CVE-2011-2527
• https://bugs.launchpad.net/qemu/+bug/807893
• https://exchange.xforce.ibmcloud.com/vulnerabilities/68539
• https://www.debian.org/security/2011/dsa-2282
• http://lists.fedoraproject.org/pipermail/package-announce/2012-June/081972.html
• http://lists.opensuse.org/opensuse-updates/2012-02/msg00009.html
• http://rhn.redhat.com/errata/RHSA-2011-1531.html
• http://secunia.com/advisories/45187
• http://secunia.com/advisories/45188
• http://secunia.com/advisories/45419
• http://secunia.com/advisories/47157
• http://secunia.com/advisories/47992
• http://ubuntu.com/usn/usn-1177-1
• http://www.openwall.com/lists/oss-security/2011/07/12/15
• http://www.openwall.com/lists/oss-security/2011/07/12/5
• http://www.osvdb.org/74752
• http://www.securityfocus.com/bid/48659