Description: | The filesystem implementation in the Linux kernel through 4.8.2 preserves the setgid bit during a setxattr call, which allows local users to gain group privileges by leveraging the existence of a setgid program with restrictions on execute permissions. Andreas Gruenbacher and Jan Kara discovered that the filesystem implementation in the Linux kernel did not clear the setgid bit during a setxattr call. A local attacker could use this to possibly elevate group privileges.
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