GHSA-jj4j-x5ww-cwh9 is a medium-severity (CVSS 5.6) CWE-863 vulnerability in ash. A fix is available for ash — see the affected versions and patch details below.
Before action, Ash's hooks may execute in certain scenarios despite a request being forbidden
Exploitation Status
No confirmed exploitation observed yet
- CISA’s own triage has not observed active exploitation or public proof-of-concept code for this CVE as of its last assessment.
Exploitation and automatability from CISA’s SSVC triage for GHSA-jj4j-x5ww-cwh9.
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.
How urgent is this, really
GHSA-jj4j-x5ww-cwh9 plotted by exploitation likelihood (EPSS) against impact (CVSS). The shaded corner — EPSS 50%+ and CVSS 7.0+ — is where this CVE doesn't sit, though severity or exploitability alone can still warrant action.
Where this sits among everything scored
Of 378,567 CVEs with a current EPSS score, this one falls in the < 10% band (highlighted). Real counts from FIRST.org, not a sample — log-scaled since the landscape is heavily right-skewed.
Real-World Exposure
ashReal-time download stats are indexed for npm and PyPI packages. This vulnerability affects Hex packages — download data is not available via public APIs for these ecosystems.
Description
Summary
Certain bulk action calls with a before_transaction hook and no after_transaction hook, will call the before_transaction hook before authorization is checked and a Forbidden error is returned, when called as a bulk action.
The impact is that a malicious user could cause a before_transaction to run even though they are not authorized to perform the whole action. The before_action could run a sensitive/expensive operation.
Impact
A malicious user could cause a before_action to run even though they are not authorized to perform the whole action.
You are affected if you have an create, update or destroy action that:
- has a before_transaction hook on it, and no after_transaction hook on it.
- is being used via an
Ash.bulk_*callback (which AshJsonApi and AshGraphql do for update/destroy actions)
Whether or not or how much it matters depends on the nature of those before_transaction callbacks. If those before_transaction callbacks are side-effectful, or just doing something like looking up some external data. If your API endpoints are behind authentication and what kind.
Severity
The severity for this was hard to gauge. before_transaction hooks are not that commonly used. Additionally, any attacker must know which of these things are available to them, be authenticated to make such a request (i.e you very rarely have policies preventing the running of anonymous queries), so privileges and inside knowledge are required. Additionally, the action will always return a forbidden error, so no information is revealed. We will evaluate and adjust the severity in the next few days as needed.
It is currently marked as High, given that we really don't know what logic folks are putting in their before_transaction hooks and it could theoretically be very bad.
Workarounds
You should update ASAP, but if for whatever reason you cannot update, you can add logic to those before_transaction hooks to prevent them from doing their logic before they should.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 💧Hex | ash | all versions | 3.5.39mix deps.update ash |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for ash, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update ash to 3.5.39 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-jj4j-x5ww-cwh9 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 Security's impact-aware SCA analyses which vulnerable code paths your application actually calls, so a match like GHSA-jj4j-x5ww-cwh9 can be triaged on real exposure rather than presence alone.
Tailored to GHSA-jj4j-x5ww-cwh9. 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-jj4j-x5ww-cwh9 in your dependencies?
O3 Security finds GHSA-jj4j-x5ww-cwh9 across Hex dependencies, including transitive ones, and its impact-aware SCA ranks findings by whether your code actually calls the vulnerable path.