GHSA-xw73-rw38-6vjc
MEDIUMClassic builder cache poisoning
EPSS Exploitation Probability
EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.
Blast Radius
github.com/docker/docker🐹github.com/moby/moby🐹github.com/moby/moby🐹github.com/docker/dockerReal-time download stats are indexed for npm and PyPI packages. This vulnerability affects Go packages — download data is not available via public APIs for these ecosystems.
Description
The classic builder cache system is prone to cache poisoning if the image is built FROM scratch.
Also, changes to some instructions (most important being HEALTHCHECK and ONBUILD) would not cause a cache miss.
An attacker with the knowledge of the Dockerfile someone is using could poison their cache by making them pull a specially crafted image that would be considered as a valid cache candidate for some build steps.
For example, an attacker could create an image that is considered as a valid cache candidate for:
FROM scratch
MAINTAINER Pawel
when in fact the malicious image used as a cache would be an image built from a different Dockerfile.
In the second case, the attacker could for example substitute a different HEALTCHECK command.
Impact
23.0+ users are only affected if they explicitly opted out of Buildkit (DOCKER_BUILDKIT=0 environment variable) or are using the /build API endpoint (which uses the classic builder by default).
All users on versions older than 23.0 could be impacted. An example could be a CI with a shared cache, or just a regular Docker user pulling a malicious image due to misspelling/typosquatting.
Image build API endpoint (/build) and ImageBuild function from github.com/docker/docker/client is also affected as it the uses classic builder by default.
Patches
Patches are included in Moby releases:
- v25.0.2
- v24.0.9
- v23.0.10
Workarounds
- Use
--no-cacheor use Buildkit if possible (DOCKER_BUILDKIT=1, it's default on 23.0+ assuming that the buildx plugin is installed). - Use
Version = types.BuilderBuildKitorNoCache = trueinImageBuildOptionsforImageBuildcall.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐹Go | github.com/docker/docker | all versions | 24.0.9 |
| 🐹Go | github.com/moby/moby | all versions | 24.0.9 |
| 🐹Go | github.com/moby/moby | ≥ 25.0.0&&< 25.0.2 | 25.0.2 |
| 🐹Go | github.com/docker/docker | ≥ 25.0.0&&< 25.0.2 | 25.0.2 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for github.com/docker/docker. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.
Fix
Update github.com/docker/docker to 24.0.9 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-xw73-rw38-6vjc is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
How O3 protects you
O3 pinpoints whether GHSA-xw73-rw38-6vjc is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.
Tailored to GHSA-xw73-rw38-6vjc. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is GHSA-xw73-rw38-6vjc in your dependencies?
O3 detects GHSA-xw73-rw38-6vjc across Go dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.