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Fencer Vulns
low 3.8

CVE-2021-3155 json

snapd created ~/snap with too-wide permissions

published 2022-02-17 4 y ago modified 2026-06-17 4 mo ago also EUVD-2021-26499

cvss
3.8
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.3%
EPSS 0.3% chance of exploitation in 30 days, percentile 17%
public exploits
0
none known

Summary

snapd 2.54.2 and earlier created ~/snap directories in user home directories without specifying owner-only permissions. This could allow a local attacker to read information that should have been private. Fixed in snapd versions 2.54.3+18.04, 2.54.3+20.04 and 2.54.3+21.10.1

Patch / fix

  • canonical snapd 2.54.3
  • snapd Debian 14, Debian 13, Debian 12 2.54-1

debian advisories DEBIAN-CVE-2021-3155

  • snapd Ubuntu 18.04 LTS 2.54.3+18.04
  • snapd Ubuntu 20.04 LTS 2.54.3+20.04.1
  • snapd Ubuntu Pro 16.04 LTS 2.54.3+16.04~esm2

ubuntu advisories UBUNTU-CVE-2021-3155

Ubuntu security data © Canonical Ltd., from https://github.com/canonical/ubuntu-security-notices 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-2021-3155 updated cvss 5.5

snapd: lax permissions of ~/snap directories in user home

  • 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

0.26% chance of exploitation in the next 30 days, higher than 17% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
CNA 3.1 3.8 CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:L/I:N/A:N
NVD 3.1 5.5 CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N
NVD 2.0 2.1 AV:L/AC:L/Au:N/C:P/I:N/A:N

Affected products

  • Canonical Ltd. snapd

Classification

Weakness
  • CWE-276 Incorrect Default Permissions

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.