| Description: | The simple_set_acl function in fs/posix_acl.c in the Linux kernel before 4.9.6 preserves the setgid bit during a setxattr call involving a tmpfs filesystem, which allows local users to gain group privileges by leveraging the existence of a setgid program with restrictions on execute permissions. NOTE: this vulnerability exists because of an incomplete fix for CVE-2016-7097. It was discovered that the Linux kernel did not clear the setgid bit during a setxattr call on a tmpfs filesystem. A local attacker could use this to gain elevated group privileges.
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