# CVE-2026-82739: Ash.Resource.Validation.Confirm leaks a confirmed field's stored value in the atomic mismatch error

> Attackers can read sensitive stored field values by triggering a confirmation mismatch error in the Ash framework.

- **Severity:** Low 2.1 (`CVSS:4.0/AV:L/AC:L/AT:P/PR:N/UI:N/VC:L/VI:N/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-2026-82739, GHSA-66cg-vj5m-8w7v

## What is CVE-2026-82739?

CVE-2026-82739 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

Generation of Error Message Containing Sensitive Information vulnerability in ash-project ash discloses the stored value of a confirmed field to an actor who fails its confirmation check.

Ash.Resource.Validation.Confirm's atomic implementation (atomic/2 in lib/ash/resource/validation/confirm.ex) built the mismatch error with its value set to the field being confirmed. When the actor supplies only the confirmation argument and not the field itself, value resolves through atomic_ref/2 to the field's current stored value, so the mismatch error echoes that stored value back to the actor. Against a confirmation guarding a sensitive attribute, an actor can submit a deliberately wrong confirmation and read the real value from the returned error. The fix reports the actor-supplied confirmation in the error instead of the stored field value.

This issue affects ash: from 2.17.20 before 3.32.2.

Weakness: CWE-209 (Generation of Error Message Containing Sensitive Information)

## Which versions are affected by CVE-2026-82739?

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


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `ash` | Hex | From 2.17.20 | 3.32.2 |

## How do I fix CVE-2026-82739?

Upgrade ash to 3.32.2 or later.

## Is CVE-2026-82739 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-82739 exists.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-82739 and fix it if it is affected.

What it is: CVE-2026-82739 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-2026-82739 exists.

Affected packages and fixed versions:
- ash (Hex): affected from 2.17.20; 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-2026-82739/ (Markdown: https://insights.sbomify.com/CVE-2026-82739/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-82739
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-82739
- OSV: https://osv.dev/vulnerability/CVE-2026-82739

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-82739/
Summaries are generated and may contain mistakes; the official description above is the record.