The process_envvars function in elf/rtld.c in the GNU C Library (aka glibc or libc6) before 2.23 allows local users to bypass a pointer-guarding protection mechanism via a zero value of the LD_POINTER_GUARD environment variable.

References

• https://nvd.nist.gov/vuln/detail/CVE-2015-8777
• https://access.redhat.com/errata/RHSA-2017:1916
• https://security.gentoo.org/glsa/201702-11
• https://sourceware.org/bugzilla/show_bug.cgi?id=18928
• http://hmarco.org/bugs/glibc_ptr_mangle_weakness.html
• http://lists.fedoraproject.org/pipermail/package-announce/2016-February/177404.html
• http://lists.opensuse.org/opensuse-security-announce/2016-02/msg00036.html
• http://lists.opensuse.org/opensuse-security-announce/2016-02/msg00037.html
• http://lists.opensuse.org/opensuse-security-announce/2016-02/msg00038.html
• http://lists.opensuse.org/opensuse-security-announce/2016-02/msg00039.html
• http://www.debian.org/security/2016/dsa-3480
• http://www.openwall.com/lists/oss-security/2016/01/20/1
• http://www.securityfocus.com/bid/81469
• http://www.securitytracker.com/id/1034811
• http://www.ubuntu.com/usn/USN-2985-1
• http://www.ubuntu.com/usn/USN-2985-2