How severe is CVE-2020-15229?

CVE-2020-15229 has a CVSS score of 9.3/10, rated CRITICAL. Immediate patching is strongly recommended.

Which packages are affected by CVE-2020-15229?

CVE-2020-15229 affects the following packages: github.com/sylabs/singularity (Go). Ecosystems affected: Go.

How do I fix CVE-2020-15229?

Update github.com/sylabs/singularity to 3.6.4 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2020-15229 is resolved across your whole dependency graph.

How do I detect CVE-2020-15229 in my Go dependencies?

Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for github.com/sylabs/singularity, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.

How do I mitigate CVE-2020-15229 if there is no patch (or I can't update yet)?

Resolve every user-supplied path to its canonical form and reject anything that escapes the intended directory, and run the component under an account that has no read or write access outside the directory it legitimately serves.

Is CVE-2020-15229 actively exploited in the wild?

No public exploit code has been indexed for CVE-2020-15229 yet. This does not mean the vulnerability cannot be exploited — absence of public exploits does not imply safety. Apply the recommended fix and use O3 Security to monitor your exposure.

What is the EPSS score for CVE-2020-15229?

CVE-2020-15229 has an EPSS (Exploit Prediction Scoring System) score of 2.0%, placing it in the 81th percentile of all CVEs. EPSS is maintained by FIRST.org and estimates the probability that a vulnerability will be exploited in the wild within the next 30 days. This score indicates relatively lower exploitation probability, though the CVSS severity should still guide your patching priority.

What type of vulnerability is CVE-2020-15229?

CVE-2020-15229 is classified as Path Traversal (CWE-22). This weakness type describe the underlying flaw category, which helps determine the potential impact and the right class of mitigation. This is a high-impact weakness class that often enables remote code execution or data exposure.

When was CVE-2020-15229 published, and has it been updated?

CVE-2020-15229 was published on October 14, 2020 and was last updated on October 24, 2026. Advisory data evolves as severity scores, affected ranges, and exploit intelligence are revised — always check the latest version of the advisory before acting.

🐹

🐹 Go

Not in CISA KEV

CRITICAL severity

CVE-2020-15229 — singularity

CRITICALFix: hpcng/singularity@eba3dea

CVE-2020-15229 is a critical-severity (CVSS 9.3) Path Traversal vulnerability in github.com/sylabs/singularity. A fix is available for github.com/sylabs/singularity — see the affected versions and patch details below.

Path traversal and files overwrite with unsquashfs in singularity

Also known asGHSA-7gcp-w6ww-2xv9

Published

Oct 14, 2020

Updated

Oct 24, 2026

Affected

1 pkg

Patched

1 / 1

Exploits

None indexed

Exploitation data as of Nov 4, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

EPSS Exploitation Probability

via FIRST.org ↗

2.0%probability of exploitation in next 30 days

Lower Risk0.00%

Lower risk than most CVEs81th percentile — riskier than 81% of all scored CVEsHighest risk

Probability of exploitation in the next 30 days, from FIRST.org EPSS.

How urgent is this, really

Where this sits among everything scored

Real-World Exposure

1 pkg affected

🐹github.com/sylabs/singularity

Real-time download stats are indexed for npm and PyPI packages. This vulnerability affects Go packages — download data is not available via public APIs for these ecosystems.

Description

Impact

Due to insecure handling of path traversal and the lack of path sanitization within unsquashfs (a distribution provided utility used by Singularity), it is possible to overwrite/create any files on the host filesystem during the extraction of a crafted squashfs filesystem.

Squashfs extraction occurs automatically for unprivileged execution of Singularity (either --without-suid installation or with allow setuid = no) when a user attempts to run an image which:

is a local SIF image or a single file containing a squashfs filesystem
is pulled from remote sources library:// or shub://

Image build is also impacted in a more serious way as it is often performed by the root user, allowing an attacker to overwrite/create files leading to a system compromise. Bootstrap methods library, shub and localimage trigger a squashfs extraction.

Patches

This issue is addressed in Singularity 3.6.4.

All users are advised to upgrade to 3.6.4 especially if they use Singularity mainly for building image as root user.

Workarounds

There is no solid workaround except to temporarily avoid use of unprivileged mode with single file images, in favor of sandbox images instead. Regarding image build, temporarily avoid building from library and shub sources, and as much as possible use --fakeroot or a VM to limit potential impact.

For more information

General questions about the impact of the advisory / changes made in the 3.6.0 release can be asked in the:

Any sensitive security concerns should be directed to: [email protected]

See our Security Policy here: https://sylabs.io/security-policy

Affected Packages

1 total 1 fixed

Ecosystem	Package	Vulnerable range	Fix
🐹Go	`github.com/sylabs/singularity`	≥ 3.1.1&&< 3.6.4	3.6.4`go get github.com/sylabs/singularity@v3.6.4`

Affected Products

3 products · 4 configurations

Application

backports sleopensuse

1 version

15.0

leapopensuse

2 versions

15.115.2

Application

singularitysylabs

≥ 3.1.1 && ≤ 3.6.3

range

Detection & mitigation playbook

Open-source dependency

Detect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for github.com/sylabs/singularity, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update github.com/sylabs/singularity to 3.6.4 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2020-15229 is resolved across your whole dependency graph.
Workarounds
Resolve every user-supplied path to its canonical form and reject anything that escapes the intended directory, and run the component under an account that has no read or write access outside the directory it legitimately serves.

Frequently Asked Questions

### Impact Due to insecure handling of path traversal and the lack of path sanitization within `unsquashfs` (a distribution provided utility used by Singularity), it is possible to overwrite/create any files on the host filesystem during the extraction of a crafted squashfs filesystem. Squashfs extraction occurs automatically for unprivileged execution of Singularity (either `--without-suid` installation or with `allow setuid = no`) when a user attempts to run an image which: - is a local SIF image or a single file containing a squashfs filesystem - is pulled from remote sources `library://