Path traversal and files overwrite with unsquashfs in singularityGHSA-7gcp-w6ww-2xv9
HIGHFix: hpcng/singularity#5611GHSA-7gcp-w6ww-2xv9 is a high-severity (CVSS 8.2) 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.
EPSS Exploitation Probability
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
github.com/sylabs/singularityReal-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://orshub://
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
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐹Go | github.com/sylabs/singularity | ≥ 3.1.1&&< 3.6.4 | 3.6.4go get github.com/sylabs/singularity@v3.6.4 |
Affected Products
backports sleopensuseleapopensusesingularitysylabsDetection & mitigation playbook
Open-source dependencyDetect
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 GHSA-7gcp-w6ww-2xv9 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
Is GHSA-7gcp-w6ww-2xv9 in your dependencies?
Find it across Go, including transitive dependencies.