Skip to content
Fencer Vulns
high 8.4

CVE-2026-33747 json

BuildKit vulnerable to malicious frontend causing file escape outside of storage root

published 2026-03-26 7 mo ago modified 2026-09-10 1 mo ago also GHSA-4c29-8rgm-jvjj , GO-2026-4858 , EUVD-2026-16518

cvss
8.4
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.5%
EPSS 0.5% chance of exploitation in 30 days, percentile 43%
public exploits
0
none known

Summary

BuildKit is a toolkit for converting source code to build artifacts in an efficient, expressive and repeatable manner. Prior to version 0.28.1, when using a custom BuildKit frontend, the frontend can craft an API message that causes files to be written outside of the BuildKit state directory for the execution context. The issue has been fixed in v0.28.1. The vulnerability requires using an untrusted BuildKit frontend set with `#syntax` or `--build-arg BUILDKIT_SYNTAX`. Using these options with a well-known frontend image like `docker/dockerfile` is not affected.

Patch / fix

  • go github.com/moby/buildkit 0.28.1
  • mobyproject buildkit 0.28.1
  • docker.io Debian 13 26.1.5+dfsg1-9+deb13u1
  • docker.io Debian 14 28.5.2+dfsg4-3

debian advisories DEBIAN-CVE-2026-33747

  • docker.io-app Ubuntu 22.04 LTS 29.1.3-0ubuntu3~22.04.2
  • docker.io-app Ubuntu 24.04 LTS 29.1.3-0ubuntu3~24.04.2
  • docker.io-app Ubuntu 26.10 29.1.3-0ubuntu5
  • docker.io-app Ubuntu 26.04 LTS 29.1.3-0ubuntu4.1
  • docker.io-app Ubuntu Pro 20.04 LTS 26.1.3-0ubuntu1~20.04.1+esm2

ubuntu advisories UBUNTU-CVE-2026-33747

Ubuntu security data © Canonical Ltd., from https://github.com/canonical/ubuntu-security-notices via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

  • govulncheck-vulndb openSUSE Leap 15.6 0.0.20260402T184258-150000.1.158.1
  • docker-stable SLES LTSS Extended Security 12 SP5, SLES 12 SP5-LTSS 24.0.9_ce-1.37.1

suse advisories SUSE-SU-2026:2578-1SUSE-SU-2026:1205-1

  • tailscale openSUSE Leap 16.0 1.104.1-bp160.1.1
  • govulncheck-vulndb openSUSE Leap 16.0 0.0.20260723T184607-160000.1.1
  • docker-stable openSUSE Tumbleweed 24.0.9_ce-18.1
  • trivy openSUSE Tumbleweed 0.70.0-1.1
  • conftest openSUSE Tumbleweed 0.67.1-2.1
  • tailscale openSUSE Tumbleweed 1.96.4-1.1

opensuse advisories openSUSE-SU-2026:22203-1openSUSE-SU-2026:21483-1openSUSE-SU-2026:11075-1openSUSE-SU-2026:10651-1openSUSE-SU-2026:10472-1openSUSE-SU-2026:10456-1

  • docker Alpine 3.24, Alpine 3.23 29.3.1-r0
  • buildkit Alpine 3.24 0.29.0-r0

alpine advisories ALPINE-CVE-2026-33747

Alpine secdb © Alpine Linux, from https://secdb.alpinelinux.org via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2026-33747 updated cvss 8.2

BuildKit: github.com/moby/buildkit: BuildKit: Arbitrary file write and code execution via untrusted frontend

  • Red Hat Assisted Installer for Red Hat OpenShift Container Platform 2 assisted/agent-preinstall-image-builder-rhel9
    affected: workaround, no fix available
  • Red Hat Confidential Compute Attestation openshift-sandboxed-containers/osc-must-gather-rhel9 Red Hat Logging Subsystem for Red Hat OpenShift openshift-logging/cluster-logging-rhel9-operator
    affected: workaround, no fix planned “Will not fix”
  • Red Hat Migration Toolkit for Containers rhmtc/openshift-migration-log-reader-rhel8, rhmtc/openshift-migration-must-gather-rhel8
    affected: workaround, no fix available
  • Red Hat Migration Toolkit for Virtualization mtv-candidate/mtv-must-gather-rhel8, migration-toolkit-virtualization/mtv-must-gather-rhel8
    affected: workaround, no fix available, no fix planned “Will not fix”
  • Red Hat Multicluster Engine for Kubernetes multicluster-engine/assisted-service-9-rhel9, multicluster-engine/assisted-installer-controller-rhel9
    affected: workaround, no fix planned “Will not fix”
  • Red Hat OpenShift Developer Tools and Services ocp-tools-4/jenkins-agent-base-rhel8
    affected: workaround, no fix available
  • Red Hat OpenShift Serverless openshift-serverless-1/kn-client-kn-rhel9, openshift-serverless-1/serverless-must-gather-rhel9, openshift-serverless-1/kn-plugin-func-func-util-rhel9 Red Hat Pen Drive Powered by Red Hat Lightspeed pen-drive/pen-drive-scanner-rhel9 Red Hat Build of Podman Desktop podman-desktop-macos-1-0, podman-desktop-windows-1-0 Red Hat Build of Podman Desktop - Tech Preview rhdesktop/rh-podman-desktop-ext-rhel-rhel10, rhdesktop/rh-podman-desktop-ext-bootc-rhel10
    affected: workaround, no fix planned “Will not fix”
  • Red Hat OpenShift AI (RHOAI) rhoai/odh-workbench-codeserver-datascience-cpu-py312-rhel9
    affected: workaround, no fix available
show 19 more
  • Red Hat OpenShift Container Platform 4 openshift-kni/commatrix, openshift4/cnf-tests-rhel8, openshift4/cnf-tests-rhel9, openshift4/kube-compare-artifacts-rhel9, openshift4/numaresources-must-gather-rhel9, openshift4/ose-secrets-store-csi-mustgather-rhel9
    affected: workaround, no fix available, no fix planned “Will not fix”
  • Red Hat OpenShift GitOps openshift-gitops-1/must-gather-rhel8 Red Hat Quay 3 quay/quay-builder-rhel8, quay/quay-builder-rhel9 Red Hat Trusted Artifact Signer rhtas/ec-rhel9
    affected: workaround, no fix available
  • Red Hat multicluster engine for Kubernetes 2.8 multicluster-engine/must-gather-rhel9 1782158798
    fixed: vendor fix RHSA-2026:30650
  • Red Hat multicluster engine for Kubernetes 2.10 multicluster-engine/must-gather-rhel9 1784849867
    fixed: vendor fix RHSA-2026:46885
  • Red Hat OpenShift API for Data Protection 1.3 oadp/oadp-mustgather-rhel9 1785177359
    fixed: vendor fix RHSA-2026:51033
  • Red Hat OpenShift API for Data Protection 1.4 oadp/oadp-mustgather-rhel9 1779770049
    fixed: vendor fix RHSA-2026:29854
  • Red Hat OpenShift API for Data Protection 1.5 oadp/oadp-mustgather-rhel9 1779770057
    fixed: vendor fix RHSA-2026:26568
  • Red Hat OpenShift AI 2.25 rhoai/odh-pipeline-runtime-minimal-cpu-py312-rhel9 1783696506, rhoai/odh-pipeline-runtime-pytorch-cuda-py312-rhel9 1783616068, rhoai/odh-pipeline-runtime-pytorch-rocm-py312-rhel9 1783664916, rhoai/odh-workbench-jupyter-minimal-cpu-py312-rhel9 1783696510, rhoai/odh-workbench-jupyter-minimal-cuda-py312-rhel9 1783664711, rhoai/odh-workbench-jupyter-minimal-rocm-py312-rhel9 1783664922, +11 more
    fixed: vendor fix RHSA-2026:42644
  • Red Hat Openshift Data Foundation 4.20 odf4/cephcsi-rhel9 1786627460, odf4/odf-cli-rhel9 1786628142, odf4/mcg-core-rhel9 1786628235, odf4/odf-console-rhel9 1786628053, odf4/mcg-rhel9-operator 1786627106, odf4/ocs-rhel9-operator 1786629478, +16 more
    fixed: vendor fix RHSA-2026:57013
  • Red Hat Openshift Data Foundation 4.22 odf4/cephcsi-rhel9 1782932114, odf4/odf-cli-rhel9 1783537001, odf4/mcg-core-rhel9 1783536000, odf4/odf-drbd-rhel9 1783537392, odf4/odf-console-rhel9 1783537586, odf4/devicefinder-rhel9 1782932104, +21 more
    fixed: vendor fix RHSA-2026:37387
  • Red Hat OpenShift Service Mesh 3.0 openshift-service-mesh 1776240392
    fixed: vendor fix RHSA-2026:9440
  • Red Hat OpenShift Service Mesh 3.1 openshift-service-mesh 1776315466
    fixed: vendor fix RHSA-2026:9448
  • Red Hat OpenShift Service Mesh 3.2 openshift-service-mesh 1776291540
    fixed: vendor fix RHSA-2026:9453
  • Red Hat Quay 3.14 quay/quay-rhel8 1788593843
    fixed: vendor fix RHSA-2026:70267
  • Red Hat Quay 3.17 quay/quay-rhel9 1779922205
    fixed: vendor fix RHSA-2026:22465
  • Red Hat Trusted Artifact Signer 1.3 rhtas 1776339099
    fixed: vendor fix RHSA-2026:10125
  • Red Hat Kernel Module Management Operator for Red Hat Openshift kmm/kernel-module-management-must-gather-rhel9 Red Hat Logical Volume Manager Storage lvms4/lvms-must-gather-rhel9 Red Hat Migration Toolkit for Applications 8 mta/mta-cli-rhel9, mta/mta-discovery-addon-rhel9 Red Hat multicluster engine for Kubernetes 2.8 multicluster-engine/hive-rhel9 1782327523, multicluster-engine/work-rhel9 1782159773, multicluster-engine/discovery-rhel9 1782158169, multicluster-engine/placement-rhel9 1782160009, multicluster-engine/console-mce-rhel9 1782157085, multicluster-engine/registration-rhel9 1782160541, +20 more Red Hat multicluster engine for Kubernetes 2.10 multicluster-engine/hive-rhel9 1784896750, multicluster-engine/work-rhel9 1784301362, multicluster-engine/discovery-rhel9 1784915379, multicluster-engine/placement-rhel9 1783986002, multicluster-engine/console-mce-rhel9 1784312384, multicluster-engine/registration-rhel9 1784418135, +24 more
    not affected: vulnerable code not present
  • Red Hat Network Observability Operator network-observability/network-observability-cli-rhel9
    not affected: component not present
  • Red Hat Node HealthCheck Operator workload-availability/node-healthcheck-must-gather-rhel9 Red Hat OpenShift API for Data Protection 1.3 oadp/oadp-velero-rhel9 1785180878, oadp/oadp-rhel9-operator 1785426166, oadp/oadp-operator-bundle 1785427055, oadp/oadp-cli-binaries-rhel9 1785180801, oadp/oadp-velero-plugin-rhel9 1785177357, oadp/oadp-velero-plugin-for-aws-rhel9 1785177325, +5 more Red Hat OpenShift API for Data Protection 1.4 oadp/oadp-velero-rhel9 1779809598, oadp/oadp-rhel9-operator 1779847451, oadp/oadp-operator-bundle 1779848257, oadp/oadp-velero-plugin-rhel9 1779243793, oadp/oadp-velero-plugin-for-aws-rhel9 1779243113, oadp/oadp-velero-plugin-for-gcp-rhel9 1779243915, +4 more Red Hat OpenShift API for Data Protection 1.5 oadp/oadp-velero-rhel9 1779808027, oadp/oadp-rhel9-operator 1779843906, oadp/oadp-non-admin-rhel9 1779243495, oadp/oadp-operator-bundle 1779844974, oadp/oadp-velero-plugin-rhel9 1779245274, oadp/oadp-velero-plugin-for-aws-rhel9 1779244577, +5 more
    not affected: vulnerable code not present

20 more not affected in the full advisory

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

CISA SSVC

Exploitation
none
Automatable
no
Technical impact
total
Assessed
7 mo ago

Exploit prediction

0.51% chance of exploitation in the next 30 days, higher than 43% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
CNA 3.1 8.4 CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
NVD 3.1 9.8 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
GitHub 3.1 8.4 CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Affected packages

ecosystem package affected fixed in
go github.com/moby/buildkit
<0.28.1
0.28.1

Affected products

  • moby buildkit

Classification

Weakness
  • CWE-22 Improper Limitation of a Pathname to a Restricted Directory

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.