---
id: CVE-2026-93318
title: >-
  A malicious image can advertise DiffIDs from another image while containing
  different layer contents
summary: >-
  A malicious image can advertise DiffIDs from another image while containing
  different layer contents. In affected versions, BuildKit could use the
  advertised DiffIDs to derive cache and snapshot identity without validating
  that they matc…
severity: high
cvss: 7.5
cvssVector: 'CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:A/VC:H/VI:H/VA:L/SC:N/SI:N/SA:N'
cwe:
  - CWE-354
vendor: moby
product: github.com/moby/buildkit
affected:
  - github.com/moby/buildkit < 0.33.1
published: '2026-10-05'
updated: '2026-10-05'
sourceUpdated: '2026-10-05T20:17:28.260'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-93318'
references:
  - url: 'https://github.com/moby/buildkit/releases/tag/v0.33.1'
    label: security@docker.com
  - url: 'https://github.com/moby/buildkit/security/advisories/GHSA-f2v9-hprr-32q3'
    label: security@docker.com
tags:
  - nvd
  - cve.org
ssvc:
  exploitation: none
  automatable: 'no'
  technicalImpact: total
  timestamp: '2026-10-05T19:06:32.028591Z'
cvssSource: cna
ingestedAt: '2026-10-05T18:29:11.202Z'
---

## Overview

A malicious image can advertise DiffIDs from another image while containing different layer contents. In affected versions, BuildKit could use the advertised DiffIDs to derive cache and snapshot identity without validating that they matched the actual layer contents.

If a BuildKit daemon with shared or persistent cache first processes such a malicious image, a later build using the victim image may mount the attacker-controlled layer contents as the base image. This can allow code from the malicious image to run in the victim build, for example by replacing a commonly executed path such as /bin/sh. The attacker-controlled code may read build secrets mounted into the build, access other build resources, alter output artifacts, or hang the build.

The issue affects both regular snapshotters and lazy-pulling snapshotters such as stargz.

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.