CVE-2026-3888
Canonical Ubuntu Linux 16.04 … 24.04
Raw vector
CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:C/C:H/I:H/A:HSummary
CVE-2026-3888 is a high-severity Privilege Chaining (CWE-268) vulnerability in Canonical Ubuntu Linux. Its CVSS base score is 7.8 (High).
Operationally, exploitation aligns with the MITRE ATT&CK technique Access Token Manipulation (T1134); ranked at the 31th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog.
The strongest mitigations our analysis identified map to AC-3 (Access Enforcement) and AC-5 (Separation of Duties) — see the control section below for these in your framework.
Deeper analysis AI-assisted summary
Synthesised by an AI model from the NVD description and linked references — a reading aid, not an authoritative source.
CVE-2026-3888 is a local privilege escalation vulnerability in snapd on Linux systems, published on 2026-03-17. It enables local attackers to obtain root privileges by re-creating snap's private /tmp directory after systemd-tmpfiles automatically cleans it up. The issue affects Ubuntu 16.04 LTS, 18.04 LTS, 20.04 LTS, 22.04 LTS, and 24.04 LTS, with a CVSS v3.1 base score of 7.8 (AV:L/AC:H/PR:L/UI:N/S:C/C:H/I:H/A:H) and is associated with CWE-268.
Local attackers with low privileges can exploit this vulnerability, which requires high attack complexity. Successful exploitation allows elevation to root privileges, providing high-impact access to confidentiality, integrity, and availability across the system due to the changed scope.
Advisories from Qualys and Ubuntu detail mitigations, including patches. Key references include the Qualys vulnerability research blog (https://blog.qualys.com/vulnerabilities-threat-research/2026/03/17/cve-2026-3888-important-snap-flaw-enables-local-privilege-escalation-to-root), Ubuntu Discourse (https://discourse.ubuntu.com/t/snapd-local-privilege-escalation-cve-2026-3888), and Ubuntu Security Notice USN-8102-1 (https://ubuntu.com/security/notices/USN-8102-1), which address the flaw in affected releases.
EU & UK References
- 🇪🇺 ENISA EUVD: EUVD-2026-12570
Vulnerability Data
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,…
more
22.04 LTS, and 24.04 LTS.
- CWE(s)
Related Threats
MITRE ATT&CK Enterprise Techniques
CVEs Like This One
Affected Assets
Mitigating Controls
Control response
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- 6 hardening rules · 6 OS baselines
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Mitigating Controls (NIST 800-53 r5) AI
Access enforcement can apply rules that block unsafe privilege combinations at runtime.
Separation of duties directly blocks assignment of privilege combinations that enable unsafe actions.
Least privilege reduces the set of privileges available for dangerous chaining.
Mitigating Controls (NIST CSF 2.0) AI
Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→CSF cross-walk (authority under review) — links open the control.
Least-privilege policy definition and enforcement directly limits unsafe privilege combinations while the control also addresses broader policy lifecycle activities.
Mitigating Controls (ISO/IEC 27001:2022 Annex A) AI
Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→ISO cross-walk (authority under review) — links open the control.
Segregation of duties reduces the chance that two distinct privileges can be combined to perform unsafe actions.
Restricting privileged access rights directly mitigates the risk of privilege chaining.
Access control policies can limit the combination of privileges that enable unsafe actions.
Managing access rights helps prevent the accumulation or chaining of privileges that lead to unsafe actions.
Controlling privileged utility programs reduces opportunities for chaining privileges to perform unsafe actions.
Information access restriction limits the ability to combine privileges for unsafe actions.
Hardening callouts derived
Configuration rules from DISA STIG baselines that bear on weaknesses of the type cited by this CVE. Each rule is shown with the relationship its mapping actually records, against the CWE it was authored against. Derived via CVE→CWE over `controls_xwalks` (authoritative rows only; rows rated `none` are excluded).
Ubuntu 22.04 (1 rule)
- V-260559 Ubuntu 22.04 LTS must ensure only users who need access to security functions are part of sudo group. prevents CWE-268
Ubuntu 24.04 (1 rule)
- V-270748 Ubuntu 24.04 LTS must ensure only users who need access to security functions are part of sudo group. prevents CWE-268
Windows 10 (1 rule)
- V-220712 Only accounts responsible for the administration of a system must have Administrator rights on the system. prevents CWE-268
Windows Server 2016 (1 rule)
- V-225007 Only administrators responsible for the member server or standalone or nondomain-joined system must have Administrator rights on the system. prevents CWE-268
Windows Server 2019 (1 rule)
- V-205746 Windows Server 2019 must only allow Administrators responsible for the member server or standalone or nondomain-joined system to have Administrator rights on the system. prevents CWE-268
Windows Server 2022 (1 rule)
- V-254428 Windows Server 2022 must only allow administrators responsible for the member server or standalone or nondomain-joined system to have Administrator rights on the system. prevents CWE-268