CVE-2026-3888: Ubuntu 16.04 LTS snapd · Privilege Chaining
Affects Ubuntu 16.04 LTS snapdSource CVE Database V5
Public exploit available (Metasploit) · CVSS 7.8 High : upgrade Ubuntu 16.04 LTS snapd to 2.75.1 as a priority.
Data as of 26 Oct 2026, 11:07 UTC
- EPSS
- 1.3% chance of exploitation in 30 days – higher than 71% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
- Patch
- Available – fixed in 2.75.1
CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:C/C:H/I:H/A:HExploitation evidence
Disclosed: evidence found.
CVE published 17 Mar 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: evidence found.
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors
A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 26 Oct 2026.
What to do
Upgrade snapd to 2.75.1.
Affected software
| Product | Affected | Fixed in |
|---|---|---|
| snapd | Affected
| Fixed in
|
GitHubsnapdpkg:github/snapdOther threats | Affected
| Fixed in
|
Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.
AI-suggested
To mitigate CVE-2026-3888, organizations should first verify if systemd-tmpfiles is configured to automatically clean snap's private /tmp directory and consider disabling or modifying this cleanup behavior to prevent directory re-creation by unprivileged users. In the absence of patches, administrators can implement strict access controls on the /tmp directory and snap-related directories to prevent unauthorized deletion or recreation. Employing mandatory access control frameworks such as AppArmor or SELinux to restrict snapd and systemd-tmpfiles operations can reduce exploitation risk. Regular auditing and monitoring of /tmp directory changes and snapd service behavior can help detect suspicious activity early. Limiting local user privileges and enforcing the principle of least privilege reduces the pool of potential attackers. Additionally, educating users about the risks of local privilege escalation and maintaining robust endpoint security controls will help mitigate the threat.
Description
CVE-2026-3888 is a local privilege escalation vulnerability in snapd on Linux systems, specifically affecting multiple Ubuntu LTS versions from 16.04 through 24.04. The flaw arises when systemd-tmpfiles is configured to automatically clean snap's private /tmp directory, allowing a local attacker to re-create this directory and escalate privileges to root. The vulnerability has a high severity score of 7.8, reflecting its potential to compromise confidentiality, integrity, and availability. Exploitation requires local access and elevated privileges but no user interaction. No known exploits are currently reported in the wild. Organizations running affected Ubuntu LTS versions with snapd and systemd-tmpfiles configured as described should prioritize patching or mitigating this issue to prevent privilege chaining attacks.
References
- ubuntu.com/security/CVE-2026-3888 (opens in a new tab)
- ubuntu.com/security/notices/USN-8102-1 (opens in a new tab)
- discourse.ubuntu.com/t/snapd-local-privilege-escalation-cve-2026-3888 (opens in a new tab)
- blog.qualys.com/vulnerabilities-threat-research/2026/03/17/cve-2026-3888-important-snap-flaw-enables-local-privilege-escalation-to-root (opens in a new tab)
- cdn2.qualys.com/advisory/2026/03/17/snap-confine-systemd-tmpfiles.txt (opens in a new tab)
- openwall.com/lists/oss-security/2026/03/18/1 (opens in a new tab)