CVE-2026-15791

Publication date 21 July 2026

Last updated 6 August 2026

Ubuntu priority

Cvss 3 Severity Score

Description

A crafted message in the BuildKit low-level build API can be used to remove the contents of the /tmp directory. The action that can normally be used to delete files inside the build container rootfs can escape into the real host temp directory.

Read the notes from the security team

Status

Show unmaintained releases

Package	Ubuntu Release	Status
docker.io	26.04 LTS resolute	Needs evaluation
	24.04 LTS noble	Needs evaluation
	22.04 LTS jammy	Needs evaluation
	20.04 LTS focal	Needs evaluation
	18.04 LTS bionic	Needs evaluation
	16.04 LTS xenial	Needs evaluation
docker.io-app	26.04 LTS resolute	Needs evaluation
	24.04 LTS noble	Needs evaluation
	22.04 LTS jammy	Needs evaluation
	20.04 LTS focal	Needs evaluation

Notes

alexmurray

Traditionally the docker.io source package contained both the library and docker application. However, in releases that contain the docker.io-app source package, the docker.io source package contains only the library whilst the docker application itself is contained in the docker.io-app package.

sbeattie

docker packages contain an embedded copy of github:moby/buildkit

Severity score breakdown

CVSS version:

Base score 1.8 · Low

Base metrics

Parameter	Value
Attack vector	Local
Attack complexity	Low
Attack requirements	Present
Privileges required	None
User interaction	Active
Vulnerable system - Confidentiality impact	None
Vulnerable system - Integrity impact	Low
Vulnerable system - Availability impact	Low
Subsequent system - Confidentiality impact	None
Subsequent system - Integrity impact	None
Subsequent system - Availability impact	None

Scores

Parameter	Value
Base score	1.8 · Low
Base + Threat score	-
Base + Environmental score	-
Base + Threat + Environmental score	-

Vector: CVSS:4.0/AV:L/AC:L/AT:P/PR:N/UI:A/VC:N/VI:L/VA:L/SC:N/SI:N/SA:N

Base score 7.5 · High