CVE-2021-41072

Published: 14 September 2021

squashfs_opendir in unsquash-2.c in Squashfs-Tools 4.5 allows Directory Traversal, a different vulnerability than CVE-2021-40153. A squashfs filesystem that has been crafted to include a symbolic link and then contents under the same filename in a filesystem can cause unsquashfs to first create the symbolic link pointing outside the expected directory, and then the subsequent write operation will cause the unsquashfs process to write through the symbolic link elsewhere in the filesystem.

From the Ubuntu Security Team

Richard Weinberger discovered that Squashfs-Tools mishandled certain malformed SQUASHFS files. An attacker could use this vulnerability to write arbitrary files to the filesystem.

Priority

Cvss 3 Severity Score

8.1

Score breakdown

Status

Package	Release	Status
squashfs-tools Launchpad, Ubuntu, Debian	impish	Released (1:4.4-2ubuntu2)
	trusty	Does not exist
	upstream	Needs triage
	bionic	Released (1:4.3-6ubuntu0.18.04.4)
	focal	Released (1:4.4-1ubuntu0.2)
	hirsute	Released (1:4.4-2ubuntu0.2)
	xenial	Released (1:4.3-3ubuntu2.16.04.3+esm1) Available with Ubuntu Pro or Ubuntu Pro (Infra-only)
	jammy	Released (1:4.4-2ubuntu2)
	Patches: upstream: https://github.com/plougher/squashfs-tools/commit/e0485802ec72996c20026da320650d8362f555bd

Severity score breakdown

Parameter	Value
Base score	8.1
Attack vector	Network
Attack complexity	Low
Privileges required	None
User interaction	Required
Scope	Unchanged
Confidentiality	None
Integrity impact	High
Availability impact	High
Vector	CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:H/A:H

References

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