Ubuntu LinuxOperating system · Canonical
CVE-2026-3888
Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.
NVD · uneditedLocal privilege escalation in snapd on Linux allows local attackers to get root privilege by re-creating snap's private /tmp directory when systemd-tmpfiles is configured to automatically clean up this directory. This issue affects Ubuntu 16.04 LTS, 18.04 LTS, 20.04 LTS, 22.04 LTS, and 24.04 LTS.
Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.
dbcve analysis · high confidenceLocal privilege escalation in snapd where a local attacker can gain root by re-creating snap's private /tmp directory when systemd-tmpfiles automatically cleans it up. The race condition between directory deletion and recreation allows privilege escalation to root.
Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.
Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.
NVD · CPE data
Ubuntu LinuxOperating system
= 16.04= 18.04= 20.04= 22.04= 24.04CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.
From the vector- Attack vector
- Local
- Complexity
- High
- Privileges
- Low
- User interaction
- None
- Scope
- Changed
- Confidentiality
- High
- Integrity
- High
- Availability
- High
CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:C/C:H/I:H/A:H
Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.
dbcve checksWork through these to decide whether this CVE applies to you.
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Identify Ubuntu versionRun `lsb_release -a` or check `/etc/lsb-release` to get the exact Ubuntu versionAffected if The version is 16.04, 18.04, 20.04, 22.04, or 24.04
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Verify snapd is installedRun `snap --version` or check if the snapd service is present via `systemctl list-units | grep snapd`Affected if snapd is installed and the system is an affected Ubuntu version
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Inspect systemd-tmpfiles configuration for snap directoriesCheck `/etc/tmpfiles.d/` and `/usr/lib/tmpfiles.d/` for files containing 'snap' entries, and run `systemd-tmpfiles --cat-config` to see active cleanup rulesAffected if systemd-tmpfiles is configured to automatically clean snap-related /tmp directories
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Check for snap private /tmp directoriesLook for directories matching `/tmp/snap-*` patterns using `ls -la /tmp/ | grep snap`Affected if Snap private /tmp directories exist on the system and are subject to automatic cleanup by systemd-tmpfiles
A system is affected if it runs an affected Ubuntu version (16.04-24.04), has snapd installed, and systemd-tmpfiles is configured to clean snap-specific /tmp directories, creating the race condition window for privilege escalation.
Generated from the published advisory. Verify against your own configuration.
Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.
dbcve · scopedReconfigure systemd-tmpfiles to exclude snap-specific /tmp directories from automatic cleanup, or apply snapd security patches when released.
Ubuntu 24.04 LTS (which includes patched snapd addressing this vulnerability)
- 1. Back up important data and verify current snapd version: snap --version
Generated from the published advisory — verify against the referenced sources before acting.
Fix this in Ubuntu Linux
Scoped from the published advisory
- Consultation3.0 h
- Implementation4.0 h
- Testing2.0 h
- Review / QA2.0 h
An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $3,168.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2026-3888 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.
References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.
Primary sourcesPractitioner notes
ContributedPeer-ranked notes from engineers who’ve handled CVE-2026-3888 in production — separate from our analysis above.
The advisory tells you what broke. It rarely tells you what actually worked. If you’ve dealt with this one, that detail is what the next engineer is searching for.
- The version that genuinely resolved it — not the one the vendor claimed
- A config change or rule that shut the vector down
- A gotcha in the upgrade path that cost you an afternoon
No notes yet
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- Verified mitigations, workarounds, and config changes
- Version or environment caveats, and links to real fixes
- No weaponised exploit code, or anything meant to cause harm
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