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

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.

Vendor	Product	Versions
ash-project	ash	0.10.0 – before 3.33.0
ash-project	ash	05848d5f4affe60fddd812222a18ada080c0813b – before *

Vendor

Product

Versions

ash-project

ash

0.10.0 – before 3.33.0

ash-project

ash

05848d5f4affe60fddd812222a18ada080c0813b – before *

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

In plain English

Official description

Affected products (as reported)

References