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Fencer Vulns
high 8.2

CVE-2020-15229 json

Path traversal and files overwrite with unsquashfs

published 2020-10-14 6 y ago modified 2026-09-10 1 mo ago also GHSA-7gcp-w6ww-2xv9 , EUVD-2021-0998

cvss
8.2
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
2.0%
EPSS 2.0% chance of exploitation in 30 days, percentile 81%
public exploits
0
none known

Summary

Singularity (an open source container platform) from version 3.1.1 through 3.6.3 has a vulnerability. Due to insecure handling of path traversal and the lack of path sanitization within `unsquashfs`, it is possible to overwrite/create any files on the host filesystem during the extraction with a crafted squashfs filesystem. The extraction occurs automatically for unprivileged (either installation or with `allow setuid = no`) run of Singularity when a user attempt to run an image which is a local SIF image or a single file containing a squashfs filesystem and is coming from remote sources `library://` or `shub://`. Image build is also impacted in a more serious way as it can be used by a root user, allowing an attacker to overwrite/create files leading to a system compromise, so far bootstrap methods `library`, `shub` and `localimage` are triggering the squashfs extraction. 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. There is no solid workaround except to temporary avoid to use unprivileged mode with single file images in favor of sandbox images instead. Regarding image build, temporary avoid to build from `library` and `shub` sources and as much as possible use `--fakeroot` or a VM for that.

Patch / fix

  • go github.com/sylabs/singularity 3.6.4
  • singularity openSUSE Tumbleweed 3.8.3-1.2
  • singularity Package Hub 15 SP2 3.6.4-bp152.2.12.1
  • singularity openSUSE Leap 15.2 3.6.4-lp152.2.9.1
  • singularity openSUSE Leap 15.1 3.6.4-lp151.2.12.1

opensuse advisories openSUSE-SU-2024:11384-1openSUSE-SU-2020:1814-1openSUSE-SU-2020:1770-1openSUSE-SU-2020:1769-1

  • singularity Alpine 3.24, Alpine 3.23, Alpine 3.22 +3 more 3.6.4-r0

alpine advisories ALPINE-CVE-2020-15229

Alpine secdb © Alpine Linux, from https://secdb.alpinelinux.org via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2020-15229 updated cvss 8.2

singularity: path traversal and files overwrite with unsquashfs

  • Red Hat All currently supported Red Hat products
    not affected: vulnerable code not present

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

Exploit prediction

2.05% chance of exploitation in the next 30 days, higher than 81% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
CNA 3.1 8.2 CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:H/A:N
NVD 3.1 9.3 CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:N
NVD 2.0 5.8 AV:N/AC:M/Au:N/C:P/I:P/A:N
GitHub 3.1 8.2 CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:H/A:N

Affected packages

ecosystem package affected fixed in
go github.com/sylabs/singularity
>=3.1.1, <3.6.4
3.6.4

Affected products

  • hpcng singularity

Classification

Weakness
  • CWE-22 Improper Limitation of a Pathname to a Restricted Directory

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.