CVE-2021-41072: squashfs_opendir in unsquash-2.c in Squashfs-Tools 4.5 allows Directory Traversal, a different vulnerability t

This month

HIGH 8.1WATCHLISTDOWNGRADEMITIGATE

CVE-2021-41072 is a high-severity flaw (CVSS 8.1) affecting squashfs-tools, debian linux. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

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

Why this priority

High severity
Public exploit reference
On your watchlist

No fix is published yet: follow the downgrade or mitigation steps.

Risk facts

CVSS score	8.1 (High)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	None
User interaction	Required
EPSS exploit chance	2.3% (top 17%)
CISA exploited list	No
Weakness	CWE-22, CWE-59
Published	2021-09-14
Last modified	2026-06-17

Publisher (CNA): MITRE · Vendor: debian · squashfs-tools project

Last updated 2026-06-17 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2021-09-14 01:15 UTCPublished CVE record published
2026-06-17 04:07 UTCUpdated Record last modified

squashfs-tools project squashfs-tools DOWNGRADE

Affected: 4.5

Fixed in: no fixed release known

Safe to downgrade to: a release before 4.5

1. Check installed version

apt-cache policy squashfs-tools || rpm -q squashfs-tools || squashfs-tools --version

2. No fixed release: DOWNGRADE to a release before 4.5 (Debian / Ubuntu)

apt-cache madison squashfs-tools sudo apt install squashfs-tools=<VERSION_BEFORE_4.5> sudo apt-mark hold squashfs-tools

2. No fixed release: DOWNGRADE (RHEL / Amazon Linux / Fedora)

dnf --showduplicates list squashfs-tools sudo dnf downgrade squashfs-tools-<VERSION_BEFORE_4.5> sudo dnf versionlock add squashfs-tools

Downgrade risk

Downgrading can break dependent software and may reopen older bugs. Read the distro advisory first and test on a non-production host.

After downgrade

Restart the service, and keep the package held until a fixed release ships.

debian debian linux MITIGATE

Affected: 9.0 · 10.0 · 11.0

Fixed in: no fixed release known

Safe to downgrade to: a release before 9.0

Check your OS release

cat /etc/os-release; uname -r

Debian / Ubuntu

sudo apt update && sudo apt full-upgrade

RHEL / Amazon Linux / Fedora

sudo dnf upgrade --refresh

Windows

Install the latest cumulative update from Windows Update

If no patch exists yet

OS downgrades are not safe. Apply the vendor mitigation from the advisory and restrict exposure.

Verify at the official source NVD · CVE Program · Report a problem with this page
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.

Quick answers

How do I fix CVE-2021-41072?

squashfs-tools: downgrade or apply the listed mitigation; debian linux: mitigate or apply the listed mitigation. Exact commands for each OS are on this page.

Is CVE-2021-41072 being exploited?

CVE-2021-41072 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

What does CVE-2021-41072 affect?

CVE-2021-41072 affects squashfs-tools, debian linux. Severity is high (CVSS 8.1). 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 filena

How urgent is CVE-2021-41072?

Priority 59/100. High severity; Public exploit reference; On your watchlist

Software pages

Debian vulnerabilities

Related CVEs

CVE-2021-40153 HIGH 8.1 DOWNGRADE MITIGATE squashfs_opendir in unsquash-1.c in Squashfs-Tools 4.5 stores the filename in the directory entry; this is the

References

← Back to latest CVEs