# CVE-2026-82744: Ash.Reactor change step fails open, skipping a change when its where guard raises

> Attackers can bypass security-relevant changes in Ash.Reactor by triggering exceptions in validation guards, causing the system to fail open and skip critical steps.

- **Severity:** Low 2.1 (`CVSS:4.0/AV:L/AC:L/AT:P/PR:N/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Local or same network only
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 1 Sep 2026
- **Updated:** 1 Sep 2026
- **Also known as:** EEF-CVE-2026-82744, GHSA-3xq4-m876-fr88

## What is CVE-2026-82744?

CVE-2026-82744 is a low-severity vulnerability in ash-project ash, published on 1 Sep 2026. It can only be exploited from the same machine or local network, with no action from the victim.

### Official description

Not Failing Securely (Failing Open) vulnerability in ash-project ash skips an Ash.Reactor change when the guard controlling it raises, so a change meant to run does not.

An Ash.Reactor change step can be gated by where validations that decide whether the change runs. Ash.Reactor.ChangeStep (lib/ash/reactor/steps/change_step.ex) evaluated those guards in apply_where_clauses/3, and apply_validation rescued any exception into {:error, error}. The reduce treated that identically to a guard whose condition was simply not met and bypassed the change. So when a guard raises (for example on attacker-influenced input), a change that enforces a security-relevant modification is skipped rather than failing the step. The fix distinguishes a raised exception (now {:raised, error}) and halts the step with an error, failing closed.

This issue affects ash: from 3.0.0-rc.17 before 3.32.2.

Weakness: CWE-636 (Not Failing Securely)

## Which versions are affected by CVE-2026-82744?

1 open source package ship an affected version, including ash.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `ash` | Hex | From 3.0.0-rc.17 | 3.32.2 |

## How do I fix CVE-2026-82744?

Upgrade ash to 3.32.2 or later.

## Is CVE-2026-82744 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-82744 exists.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-82744 and fix it if it is affected.

What it is: CVE-2026-82744 is a low-severity vulnerability in ash-project ash, published on 1 Sep 2026. It can only be exploited from the same machine or local network, with no action from the victim.
Exploitation: It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-82744 exists.

Affected packages and fixed versions:
- ash (Hex): affected from 3.0.0-rc.17; fixed in 3.32.2

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-82744/ (Markdown: https://insights.sbomify.com/CVE-2026-82744/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-82744
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-82744
- OSV: https://osv.dev/vulnerability/CVE-2026-82744

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-82744/
Summaries are generated and may contain mistakes; the official description above is the record.