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CVE-2021-4037

Description

A vulnerability was found in the fs/inode.c:inode_init_owner() function logic of the LInux kernel that allows local users to create files for the XFS file-system with an unintended group ownership and with group execution and SGID permission bits set, in a scenario where a directory is SGID and belongs to a certain group and is writable by a user who is not a member of this group. This can lead to excessive permissions granted in case when they should not. This vulnerability is similar to the previous CVE-2018-13405 and adds the missed fix for the XFS.

POC

Reference

- https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=01ea173e103e

- https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=0fa3ecd87848

Github

- https://github.com/ARPSyndicate/cvemon