Canonical Ubuntu Linux up to 2.75.0 snapd /tmp privilege chaining

CVSS Meta Temp Score CVSS is a standardized scoring system to determine possibilities of attacks. The Temp Score considers temporal factors like disclosure, exploit and countermeasures. The unique Meta Score calculates the average score of different sources to provide a normalized scoring system.	Current Exploit Price (≈) Our analysts are monitoring exploit markets and are in contact with vulnerability brokers. The range indicates the observed or calculated exploit price to be seen on exploit markets. A good indicator to understand the monetary effort required for and the popularity of an attack.	CTI Interest Score Our Cyber Threat Intelligence team is monitoring different web sites, mailing lists, exploit markets and social media networks. The CTI Interest Score identifies the interest of attackers and the security community for this specific vulnerability in real-time. A high score indicates an elevated risk to be targeted for this vulnerability.
7.2	$0-$5k	0.00

Summaryinfo

A vulnerability classified as critical has been found in Canonical Ubuntu Linux up to 2.75.0. This impacts an unknown function of the file /tmp of the component snapd. The manipulation leads to privilege chaining. This vulnerability is documented as CVE-2026-3888. The attack needs to be performed locally. There is not any exploit available. It is recommended to upgrade the affected component.

Detailsinfo

A vulnerability, which was classified as critical, has been found in Canonical Ubuntu Linux up to 2.75.0. This issue affects some unknown processing of the file /tmp of the component snapd. The manipulation with an unknown input leads to a privilege chaining vulnerability. Using CWE to declare the problem leads to CWE-268. Two distinct privileges, roles, capabilities, or rights can be combined in a way that allows an entity to perform unsafe actions that would not be allowed without that combination. Impacted is confidentiality, integrity, and availability. The summary by CVE is:

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.

The weakness was released with Qualys Security Advisory Team. It is possible to read the advisory at ubuntu.com. The identification of this vulnerability is CVE-2026-3888 since 03/10/2026. The exploitation is known to be difficult. Attacking locally is a requirement. Technical details of the vulnerability are known, but there is no available exploit. The attack technique deployed by this issue is T1068 according to MITRE ATT&CK.

The vulnerability scanner Nessus provides a plugin with the ID 302821 (Linux Distros Unpatched Vulnerability : CVE-2026-3888), which helps to determine the existence of the flaw in a target environment.

Upgrading to version 2.75.1 eliminates this vulnerability.

The vulnerability is also documented in the databases at Tenable (302821) and EUVD (EUVD-2026-12570). Statistical analysis made it clear that VulDB provides the best quality for vulnerability data.

Productinfo

Type

• Operating System

Vendor

• Canonical

Name

• Ubuntu Linux

Version

• 2.0
• 2.1
• 2.2
• 2.3
• 2.4
• 2.5
• 2.6
• 2.7
• 2.8
• 2.9
• 2.10
• 2.11
• 2.12
• 2.13
• 2.14
• 2.15
• 2.16
• 2.17
• 2.18
• 2.19
• 2.20
• 2.21
• 2.22
• 2.23
• 2.24
• 2.25
• 2.26
• 2.27
• 2.28
• 2.29
• 2.30
• 2.31
• 2.32
• 2.33
• 2.34
• 2.35
• 2.36
• 2.37
• 2.38
• 2.39
• 2.40
• 2.41
• 2.42
• 2.43
• 2.44
• 2.45
• 2.46
• 2.47
• 2.48
• 2.49
• 2.50
• 2.51
• 2.52
• 2.53
• 2.54
• 2.55
• 2.56
• 2.57
• 2.58
• 2.59
• 2.60
• 2.61
• 2.62
• 2.63
• 2.64
• 2.65
• 2.66
• 2.67
• 2.68
• 2.69
• 2.70
• 2.71
• 2.72
• 2.73
• 2.74
• 2.75.0

License

• open-source

CPE 2.3info

• 🔒
• 🔒
• 🔒

CPE 2.2info

• 🔒
• 🔒
• 🔒

CVSSv4info

VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 7.4
VulDB Meta Temp Score: 7.2

VulDB Base Score: 7.0
VulDB Temp Score: 6.7
VulDB Vector: 🔒
VulDB Reliability: 🔍

CNA Base Score: 7.8
CNA Vector (canonical): 🔒

CVSSv2info

AV	AC	Au	C	I	A
💳	💳	💳	💳	💳	💳
💳	💳	💳	💳	💳	💳
💳	💳	💳	💳	💳	💳

Vector	Complexity	Authentication	Confidentiality	Integrity	Availability
Unlock	Unlock	Unlock	Unlock	Unlock	Unlock
Unlock	Unlock	Unlock	Unlock	Unlock	Unlock
Unlock	Unlock	Unlock	Unlock	Unlock	Unlock

VulDB Base Score: 🔒
VulDB Temp Score: 🔒
VulDB Reliability: 🔍

Exploitinginfo

Class: Privilege chaining
CWE: CWE-268 / CWE-266
CAPEC: 🔒
ATT&CK: 🔒

Physical: Partially
Local: Yes
Remote: No

Availability: 🔒
Status: Not defined

EPSS Score: 🔒
EPSS Percentile: 🔒

Price Prediction: 🔍
Current Price Estimation: 🔒

0-Day	Unlock	Unlock	Unlock	Unlock
Today	Unlock	Unlock	Unlock	Unlock

Nessus ID: 302821
Nessus Name: Linux Distros Unpatched Vulnerability : CVE-2026-3888

Threat Intelligenceinfo

Interest: 🔍
Active Actors: 🔍
Active APT Groups: 🔍

Countermeasuresinfo

Recommended: Upgrade
Status: 🔍

0-Day Time: 🔒

Upgrade: Ubuntu Linux 2.75.1

Timelineinfo

03/10/2026 CVE reserved
03/17/2026 +7 days Advisory disclosed
03/17/2026 +0 days VulDB entry created
03/21/2026 +4 days VulDB entry last update

Sourcesinfo

Advisory: ubuntu.com
Organization: Qualys Security Advisory Team
Status: Confirmed

CVE: CVE-2026-3888 (🔒)
GCVE (CVE): GCVE-0-2026-3888
GCVE (VulDB): GCVE-100-351371
EUVD: 🔒

Entryinfo

Created: 03/17/2026 16:39
Updated: 03/21/2026 18:45
Changes: 03/17/2026 16:39 (66), 03/17/2026 17:33 (1), 03/18/2026 08:21 (2), 03/21/2026 18:45 (1)
Complete: 🔍
Cache ID: 216::103

Statistical analysis made it clear that VulDB provides the best quality for vulnerability data.

Discussion

Are you interested in using VulDB?

Download the whitepaper to learn more about our service!