CVE-2026-3888

HIGH

Local Privilege Escalation in snapd

Title source: cna
STIX 2.1

Exploitation Summary

EIP tracks 7 public exploits for CVE-2026-3888. PoCs published by hewhomusntbenamed, DanielTangnes, nomaisthere.

AI-analyzed exploit summary This repository contains a functional exploit for CVE-2026-3888, a local privilege escalation (LPE) vulnerability in snap-confine and systemd-tmpfiles. The exploit leverages a race condition to swap directories and inject a malicious payload, achieving root access.

Description

Local 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.

Exploits (7)

nomisec WORKING POC
by hewhomusntbenamed · poc
https://github.com/hewhomusntbenamed/CVE-2026-3888-fixed

This repository contains a functional exploit for CVE-2026-3888, a local privilege escalation (LPE) vulnerability in snap-confine and systemd-tmpfiles. The exploit leverages a race condition to swap directories and inject a malicious payload, achieving root access.

Classification
Working Poc 95%
Attack Type
Lpe
Complexity
Complex
Reliability
Racy
Target: snap-confine and systemd-tmpfiles
No auth needed
Prerequisites: snap-confine installed · systemd-tmpfiles installed · specific directory structure and permissions
devstral-2 · analyzed May 12, 2026 Full analysis →
nomisec WORKING POC
by DanielTangnes · poc
https://github.com/DanielTangnes/CVE-2026-3888

This repository contains a functional privilege escalation exploit for CVE-2026-3888, targeting a race condition in snap-confine to achieve root access. The exploit involves namespace manipulation and dynamic linker hijacking via a crafted library.

Classification
Working Poc 95%
Attack Type
Lpe
Complexity
Complex
Reliability
Racy
Target: snap-confine (Firefox snap sandbox)
Auth required
Prerequisites: SSH access to target · x86_64 attack box · specific snap environment
devstral-2 · analyzed Apr 09, 2026 Full analysis →
nomisec WRITEUP
by nomaisthere · poc
https://github.com/nomaisthere/CVE-2026-3888

This repository provides a detailed technical analysis of CVE-2026-3888, a local privilege escalation vulnerability in Ubuntu 24.04 involving the interaction between snap-confine and systemd-tmpfiles. It includes in-depth explanations of the race condition, exploitation steps, and mitigations.

Classification
Writeup 100%
Attack Type
Lpe
Complexity
Complex
Reliability
Racy
Target: Ubuntu Desktop >= 24.04 (snapd < 2.74.2)
No auth needed
Prerequisites: Access to a vulnerable Ubuntu system · Ability to execute snaps · systemd-tmpfiles cleanup window
devstral-2 · analyzed Mar 24, 2026 Full analysis →
nomisec WORKING POC
by TheCyberGeek · poc
https://github.com/TheCyberGeek/CVE-2026-3888-snap-confine-systemd-tmpfiles-LPE

This repository contains a functional local privilege escalation (LPE) exploit for CVE-2026-3888, targeting a TOCTOU race condition between `snap-confine` and `systemd-tmpfiles` on Ubuntu 24.04+. Two variants are provided: SUID and Capabilities, both leveraging race conditions to overwrite critical files and escalate privileges to root.

Classification
Working Poc 100%
Attack Type
Lpe
Complexity
Complex
Reliability
Racy
Target: snapd < 2.74.2 on Ubuntu 24.04+
No auth needed
Prerequisites: Ubuntu 24.04+ with unpatched snapd (< 2.74.2) · SUID-root `snap-confine` · Installed snap with layout bind-mounts (e.g., firefox, snap-store) · Active `systemd-tmpfiles-clean.timer` · Presence of `/usr/bin/busybox`
devstral-2 · analyzed Mar 24, 2026 Full analysis →
nomisec WORKING POC
by netw0rk7 · poc
https://github.com/netw0rk7/CVE-2026-3888-PoC

This PoC exploits a race condition in the Snap package manager (hello-world snap) to achieve local privilege escalation by symlinking a malicious shared library into a target directory. The payload executes arbitrary commands with elevated privileges upon successful exploitation.

Classification
Working Poc 95%
Attack Type
Lpe
Complexity
Moderate
Reliability
Racy
Target: Snap package manager (hello-world snap)
No auth needed
Prerequisites: Compiled shared library payload · Presence of the hello-world snap
devstral-2 · analyzed Mar 20, 2026 Full analysis →
nomisec SCANNER
by Many-Hat-Group · poc
https://github.com/Many-Hat-Group/Ubuntu-CVE-2026-3888-patcher

This repository contains a bash script designed to detect and remediate CVE-2026-3888 on Ubuntu systems by checking the installed version of snapd and applying patches if necessary. It does not exploit the vulnerability but instead automates the patching process.

Classification
Scanner 95%
Attack Type
Other
Complexity
Moderate
Reliability
Reliable
Target: snapd on Ubuntu
Auth required
Prerequisites: root access · Ubuntu system with snapd installed
devstral-2 · analyzed Mar 19, 2026 Full analysis →
nomisec WORKING POC
by fevar54 · poc
https://github.com/fevar54/CVE-2026-3888-POC-all-from-the-Qualys-platform.

This repository contains a functional PoC for CVE-2026-3888, a local privilege escalation vulnerability in snapd. The exploit leverages a race condition between snap-confine and systemd-tmpfiles to recreate the /tmp/.snap directory with malicious files, leading to root privilege execution.

Classification
Working Poc 95%
Attack Type
Lpe
Complexity
Moderate
Reliability
Racy
Target: snapd on Ubuntu 16.04 LTS, 18.04 LTS, 20.04 LTS, 22.04 LTS, and 24.04 LTS
No auth needed
Prerequisites: Ubuntu system with snapd installed · gcc for compiling the malicious library · /tmp/.snap directory must be deleted by systemd-tmpfiles
devstral-2 · analyzed Mar 19, 2026 Full analysis →

References (6)

Core 6
Core References
Vdb Entry, Issue Tracking vdb-entry issue-tracking
https://ubuntu.com/security/CVE-2026-3888
Vendor Advisory vendor-advisory
https://ubuntu.com/security/notices/USN-8102-1
Vendor Advisory technical-description vendor-advisory
https://discourse.ubuntu.com/t/snapd-local-privilege-escalation-cve-2026-3888
Technical Description, Media Coverage technical-description media-coverage
https://cdn2.qualys.com/advisory/2026/03/17/snap-confine-systemd-tmpfiles.txt

Scores

CVSS v3 7.8
EPSS 0.0038
EPSS Percentile 29.9%
Attack Vector LOCAL
CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:C/C:H/I:H/A:H

CISA SSVC

Vulnrichment
Exploitation none
Automatable no
Technical Impact total

Details

CWE
CWE-268
Status published
Products (11)
Canonical/Ubuntu 16.04 LTS 2.61.4ubuntu0.16.04.1+esm2
Canonical/Ubuntu 18.04 LTS 2.61.4ubuntu0.18.04.1+esm2
Canonical/Ubuntu 20.04 LTS 2.67.1+20.04ubuntu1~esm1
Canonical/Ubuntu 22.04 LTS 2.73+ubuntu22.04.1
Canonical/Ubuntu 24.04 LTS 2.73+ubuntu24.04.1
Canonical/Ubuntu 24.04 LTS 2.73+ubuntu24.04.2
canonical/ubuntu_linux 16.04
canonical/ubuntu_linux 18.04
canonical/ubuntu_linux 20.04
canonical/ubuntu_linux 22.04
... and 1 more
Published Mar 17, 2026
Tracked Since Mar 17, 2026