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Rewterz Threat Advisory – Multiple Util-Linux Libmount Vulnerabilities

Severity

High

Analysis Summary

CVE-2021-3996

util-linux could allow a local authenticated attacker to bypass security restrictions, caused by a flaw when parsing /proc/self/mountinfo in libmount. By sending a specially-crafted request, an attacker could exploit this vulnerability to unmount other users’ filesystems that are either world-writable or mounted in a world-writable directory.

CVE-2021-3995 

util-linux could allow a local authenticated attacker to bypass security restrictions, caused by a improper user uid comparison by the is_fuse_usermount function in libmount. By sending a specially-crafted request, an attacker could exploit this vulnerability to unmount the FUSE filesystems that belong to certain other users.

Impact

  • Security Bypass

Affected Vendors

  • Linux

Affected Products

  • util-linux util-linux 2.36.2

Remediation

Upgrade to the latest version of util-linux, available from the util-linux GIT Repository.

https://github.com/util-linux/util-linux/commits/stable/v2.37

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