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.
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Sat, 05 Sep 2026 17:30:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| 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. | |
| Title | Ash string length constraints count graphemes, so a combining-mark string of any size passes max_length | |
| First Time appeared |
Ash-project
Ash-project ash |
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| Weaknesses | CWE-1284 | |
| CPEs | cpe:2.3:a:ash-project:ash:*:*:*:*:*:*:*:* | |
| Vendors & Products |
Ash-project
Ash-project ash |
|
| References |
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| Metrics |
cvssV4_0
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Status: PUBLISHED
Assigner: EEF
Published:
Updated: 2026-09-05T17:16:16.722Z
Reserved: 2026-08-31T01:00:10.817Z
Link: CVE-2026-82752
No data.
Status : Received
Published: 2026-09-05T18:17:29.170
Modified: 2026-09-05T18:17:29.170
Link: CVE-2026-82752
No data.
OpenCVE Enrichment
Updated: 2026-09-05T20:00:05Z