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.
See https://bugs.gentoo.org/811474#c2 (meant to tag this bug and somehow didn't).
Arbitrary file writes are arbitrary code execution. Upgrading severity for both.
GLSA request filed
The bug has been referenced in the following commit(s):
Author: GLSAMaker <firstname.lastname@example.org>
AuthorDate: 2023-05-30 02:54:28 +0000
Commit: John Helmert III <email@example.com>
CommitDate: 2023-05-30 02:56:35 +0000
[ GLSA 202305-29 ] squashfs-tools: Multiple Vulnerabilities
Signed-off-by: GLSAMaker <firstname.lastname@example.org>
Signed-off-by: John Helmert III <email@example.com>
glsa-202305-29.xml | 44 ++++++++++++++++++++++++++++++++++++++++++++
1 file changed, 44 insertions(+)
GLSA released, all done!