# CVE-2026-82752: Ash string length constraints count graphemes, so a combining-mark string of any size passes max_length

> Attackers can bypass string length limits by using combining marks, causing unbounded storage growth and potential denial of service in applications using the Ash framework.

- **Severity:** Medium 5.9 (`CVSS:4.0/AV:L/AC:L/AT:P/PR:N/UI:N/VC:N/VI:L/VA:H/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:** 5 Sep 2026
- **Updated:** 8 Sep 2026
- **Also known as:** EEF-CVE-2026-82752, GHSA-cwjv-574p-59f6

## What is CVE-2026-82752?

CVE-2026-82752 is a medium-severity denial of service vulnerability in ash-project ash, published on 5 Sep 2026. It can only be exploited from the same machine or local network, with no action from the victim.

### Official description

Improper Validation of Specified Quantity in Input vulnerability in ash-project ash allows an attacker to store a value of arbitrary size in an attribute whose length constraint should bound it.

Ash measures string length with Elixir's String.length/1, which counts Unicode graphemes, in the max_length and min_length constraints of Ash.Type.String (apply_constraints/2 in lib/ash/type/string.ex), in Ash.Resource.Validation.StringLength, and in the string_length expression function. A grapheme carries an unbounded number of combining marks, so a base character followed by a million combining acute accents is one grapheme and megabytes of data, and satisfies max_length: 2. Where the data layer imposes no independent limit (ETS, Mnesia, or a Postgres text column) the whole value is persisted, so an attacker can write an entire request body into an attribute declared with a small maximum and grow storage without bound.

The counting unit also disagrees with the storage layer, which counts codepoints rather than graphemes, so a value accepted by the constraint can still be rejected or truncated by the column. A Postgres varchar(n) column bounds the value itself and is not exposed.

This issue affects ash: from 0.10.0 before 3.33.0.

Weakness: CWE-1284 (Improper Validation of Specified Quantity in Input)

## Which versions are affected by CVE-2026-82752?

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


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `ash` | Hex | From 0.10.0 | 3.33.0 |

## How do I fix CVE-2026-82752?

Upgrade ash to 3.33.0 or later.

## Is CVE-2026-82752 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-82752 exists.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-82752 and fix it if it is affected.

What it is: CVE-2026-82752 is a medium-severity denial of service vulnerability in ash-project ash, published on 5 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-2026-82752 exists.

Affected packages and fixed versions:
- ash (Hex): affected from 0.10.0; fixed in 3.33.0

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-2026-82752/ (Markdown: https://insights.sbomify.com/CVE-2026-82752/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-82752
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-82752
- OSV: https://osv.dev/vulnerability/CVE-2026-82752

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-82752/
Summaries are generated and may contain mistakes; the official description above is the record.