# CVE-2026-82746: Ash.update_many/4 atomic path skips resource policy authorization, allowing updates to forbidden records

> Attackers can bypass resource policies to modify forbidden records in Ash applications using the atomic update_many function.

- **Severity:** Medium 5.9 (`CVSS:4.0/AV:L/AC:L/AT:P/PR:N/UI:N/VC:N/VI:H/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-2026-82746, GHSA-j7c9-3fw3-jc64

## What is CVE-2026-82746?

CVE-2026-82746 is a medium-severity missing authorization 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

Missing Authorization vulnerability in ash-project ash allows an actor to update records forbidden by resource policies through the atomic path of Ash.update_many/4.

Ash.update_many/4 runs as a single atomic statement (a data-layer update_many, for example a SQL MERGE) whenever an atomic strategy is used and the data layer supports it. Ash.Actions.Update.UpdateMany (lib/ash/actions/update/update_many.ex) took that path even under authorize?: true without applying the resource's policies, so the statement updated every row matched by primary key regardless of the policy filter that authorization would impose. An actor could therefore update records the policies forbid, such as rows belonging to another actor or tenant. The fix restricts the atomic path to data layers supporting changeset filters when authorizing, authorizes each changeset, and merges the resulting policy filter into each changeset so the statement only touches authorized rows.

This issue affects ash: from 3.29.0 before 3.32.2.

Weakness: CWE-862 (Missing Authorization)

## Which versions are affected by CVE-2026-82746?

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


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `ash` | Hex | From 3.29.0 | 3.32.2 |

## How do I fix CVE-2026-82746?

Upgrade ash to 3.32.2 or later.

## Is CVE-2026-82746 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-82746 exists.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-82746 and fix it if it is affected.

What it is: CVE-2026-82746 is a medium-severity missing authorization 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-2026-82746 exists.

Affected packages and fixed versions:
- ash (Hex): affected from 3.29.0; 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-2026-82746/ (Markdown: https://insights.sbomify.com/CVE-2026-82746/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-82746
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-82746
- OSV: https://osv.dev/vulnerability/CVE-2026-82746

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-82746/
Summaries are generated and may contain mistakes; the official description above is the record.