CVE-2021-40153
CVSS v3
8.1
HIGH
EPSS Score
2.5 %
exploit probability, as of 2026-09-25
CISA KEV
No
known exploited
Exploitation
—
SSVC status
Description
squashfs_opendir in unsquash-1.c in Squashfs-Tools 4.5 stores the filename in the directory entry; this is then used by unsquashfs to create the new file during the unsquash. The filename is not validated for traversal outside of the destination directory, and thus allows writing to locations outside of the destination.
Technical details
- Published
- 2021-08-27
Frequently asked questions
What is CVE-2021-40153?
squashfs_opendir in unsquash-1.c in Squashfs-Tools 4.5 stores the filename in the directory entry; this is then used by unsquashfs to create the new file during the unsquash. The filename is not validated for traversal outside of the destination directory, and thus allows writing to locations outside of the destination.
Is CVE-2021-40153 actively exploited?
Active exploitation of CVE-2021-40153 has not been confirmed. Its EPSS score was 2.5% on 2026-09-25, the estimated probability of exploitation in the next 30 days.
What is the CVSS score for CVE-2021-40153?
CVE-2021-40153 has a CVSS v3 base score of 8.1 (HIGH severity).
Is CVE-2021-40153 affecting your environment?
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