<?xml version="1.0" encoding="UTF-8"?> <!DOCTYPE glsa SYSTEM "http://www.gentoo.org/dtd/glsa.dtd"> <glsa id="201603-04"> <title>FUSE: incorrect filtering of environment variables leading to privilege escalation </title> <synopsis>The fusermount binary in FUSE does not properly clear the environment before invoking mount or umount as root that allows a local user to overwrite arbitrary files. </synopsis> <product type="ebuild">fuse</product> <announced>2016-03-09</announced> <revised count="1">2016-03-09</revised> <bug>550152</bug> <access>local</access> <affected> <package name="sys-fs/fuse" auto="yes" arch="*"> <unaffected range="ge">2.9.4</unaffected> <vulnerable range="lt">2.9.4</vulnerable> </package> </affected> <background> <p>FUSE provides an interface for filesystems implemented in userspace.</p> </background> <description> <p>The fusermount binary calls setuid(geteuid()) to reset the RUID when it invokes /bin/mount so that it can use privileged mount options that are normally restricted if RUID != EUID. FUSE does not properly clear environment variables before invoking mount or umount as root allowing this to be passed to operations using elevated privileges such as LIBMOUNT_MTAB that is used by the mount commands debugging feature. </p> </description> <impact type="normal"> <p>The FUSE vulnerability allows a local, unprivileged user to overwrite arbitrary files on the system. </p> </impact> <workaround> <p>There is no known work around at this time.</p> </workaround> <resolution> <p>All FUSE users should upgrade to the latest version:</p> <code> # emerge --sync # emerge --ask --oneshot --verbose ">=sys-fs/fuse-2.9.4" </code> </resolution> <references> <uri link="https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2015-3202"> CVE-2015-3202 </uri> </references> <metadata tag="requester" timestamp="2015-09-09T05:09:39Z"> BlueKnight </metadata> <metadata tag="submitter" timestamp="2016-03-09T17:59:40Z">b-man</metadata> </glsa>