DescriptionThe Linux kernel through 3.17.4 does not properly restrict dropping of supplemental group memberships in certain namespace scenarios, which allows local users to bypass intended file permissions by leveraging a POSIX ACL containing an entry for the group category that is more restrictive than the entry for the other category, aka a "negative groups" issue, related to kernel/groups.c, kernel/uid16.c, and kernel/user_namespace.c.
SourceCVE (at NVD; CERT, LWN, oss-sec, fulldisc, bugtraq, EDB, Metasploit, Red Hat, Ubuntu, Gentoo, SUSE bugzilla/CVE, Mageia, GitHub code/issues, web search, more)
NVD severitymedium (attack range: local)

Vulnerable and fixed packages

The table below lists information on source packages.

Source PackageReleaseVersionStatus
linux (PTS)wheezy3.2.78-1fixed
wheezy (security)3.2.96-3fixed
jessie (security)3.16.51-3+deb8u1fixed
stretch (security), stretch4.9.82-1+deb9u3fixed
buster, sid4.15.4-1fixed

The information below is based on the following data on fixed versions.

PackageTypeReleaseFixed VersionUrgencyOriginDebian Bugs
linuxsourcewheezy(not affected)
linux-2.6source(unstable)(not affected)


[wheezy] - linux <not-affected> (User namespaces only usable in later kernels)
- linux-2.6 <not-affected> (User namespaces only usable in later kernels)

Search for package or bug name: Reporting problems