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Public proof of conceptFix available

CVE-2021-44731

A public proof of concept exists; no exploitation attested.

  • Published2022-02-17
  • WeaknessCWE-362

Am I affected?

With a domain, we read the version its public headers and pages expose. A distribution build can carry the fix under an older number.

Description

A race condition existed in the snapd 2.54.2 snap-confine binary when preparing a private mount namespace for a snap. This could allow a local attacker to gain root privileges by bind-mounting their own contents inside the snap's private mount namespace and causing snap-confine to execute arbitrary code and hence gain privilege escalation. Fixed in snapd versions 2.54.3+18.04, 2.54.3+20.04 and 2.54.3+21.10.1

Timeline

dates in UTC
  1. 2022-02-1723:15CVE publishedNVD

Observed activity

isMalicious corpus · updated 2026-11-03 21:37 UTC
Indicators tagged with this CVE, per day0 indicators over 7 days
Block these indicators
  • Firewall list (EDL, text): https://api.ismalicious.com/edl/cve/CVE-2021-44731?format=txt
  • CSV export: https://api.ismalicious.com/edl/cve/CVE-2021-44731?format=csv
  • TAXII collection of exploited CVEs
  • The EDL and CSV take an API key on the Pro plan.

Versions per branch

NVD
Canonical ubuntu linux
BranchAffectedFixed in
18.4= 18.04no fix published
20.4= 20.04no fix published
21.10= 21.10no fix published
Debian debian linux
BranchAffectedFixed in
10.0= 10.0no fix published
11.0= 11.0no fix published
Fedoraproject fedora
BranchAffectedFixed in
34.x= 34no fix published
35.x= 35no fix published

1 more product in the sources.

as publishedRanges as NVD and OSV publish them; a distribution’s build can be fixed under an older number.

Distribution builds and vendor advisories

Packages from OSV.dev and products from the vendors' CSAF advisories.

version not verifiedVersions not verified: read as OSV.dev and the vendors publish them, not checked against each vendor's release list.

Packages

  • snapdUbuntu:Pro:16.04:LTSall versions · fixed in 2.54.3+16.04~esm2
  • snapdUbuntu:Pro:14.04:LTSall versions · fixed in 2.54.3+14.04~esm1
  • snapdUbuntu:20.04:LTSall versions · fixed in 2.54.3+20.04.1
  • snapdUbuntu:20.04:LTSall versions · fixed in 2.54.3+20.04
  • snapdUbuntu:18.04:LTSall versions · fixed in 2.54.3+18.04
  • snapdDebian:14all versions · fixed in 2.54.3-1
  • snapdDebian:13all versions · fixed in 2.54.3-1
  • snapdDebian:12all versions · fixed in 2.54.3-1

2 more package ranges on OSV.dev

Vendor advisories

  • CVE-2021-44731 Red Hat Product Security

    snapd: Race condition in snap-confine's setup_private_mount()

Full record on NVD

Fix

Advisories and patches

Detection

read 2026-11-03 22:42 UTC
Nuclei template
none so far
ProjectDiscovery
Exploit-DB
no entry
Exploit-DB
Proof-of-concept repositories
1 repository, unverifieddeeexcee-io/CVE-2021-44731-snap-confine-SUID
PoC-in-GitHub
Metasploit modules
none listed
Metasploit Framework

Sources

  • CNACVSS 3.17.8known since 2026-10-23
  • NVDCVSS 3.17.8read 2026-10-23
  • NVDCVSS 2.06.9read 2026-10-23
  • CNAweakness (CWE)CWE-362known since 2026-10-23
  • NVDweakness (CWE)CWE-362read 2026-10-23
  • FIRST EPSSEPSS score1.0 %2026-11-03
  • PoC-in-GitHubproof of concept1read 2026-11-03
  • OSVaffected packages—

Identifiers

Technical details

CVSS v3 Vector
CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:C/C:H/I:H/A:H
Published
2022-02-17
Last Modified
2026-06-17
NVD status
Modified

Frequently asked questions

What is CVE-2021-44731?

A race condition existed in the snapd 2.54.2 snap-confine binary when preparing a private mount namespace for a snap. This could allow a local attacker to gain root privileges by bind-mounting their own contents inside the snap's private mount namespace and causing snap-confine to execute arbitrary code and hence gain privilege escalation. Fixed in snapd versions 2.54.3+18.04, 2.54.3+20.04 and 2.54.3+21.10.1

Is CVE-2021-44731 actively exploited?

Active exploitation of CVE-2021-44731 has not been confirmed. Its EPSS score was 1.0% on 2026-11-03, the estimated probability of exploitation in the next 30 days.

What is the CVSS score for CVE-2021-44731?

CVE-2021-44731 has a CVSS v3 base score of 7.8 (HIGH severity), with vector string CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:C/C:H/I:H/A:H.

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