Vulnerability · Published Sep 1, 2026 · Assigned by EEF
CVE-2026-82736Ash.Type.CiString validates length and match constraints before case folding, allowing constraint bypass
Low 2.1
In plain English
A low-severity security flaw in ash from ash-project. Proof-of-concept exploit code is public. The chance it is exploited in the next 30 days is estimated at 0.2% (higher than 8% of all known vulnerabilities).
Official description
Incorrect Behavior Order: Validate Before Canonicalize vulnerability in ash-project ash lets an attacker store a case-insensitive string value that violates its length or match constraints. Ash.Type.CiString.apply_constraints/2 (lib/ash/type/ci_string.ex) validated the max_length, min_length, and match constraints against the value as submitted, while the type case-folds the string (per its casing) for storage and comparison. Because validation ran before folding, an attacker can submit a value whose folded form breaks a constraint but whose original form passes: for example, against a match pattern requiring uppercase, an uppercase value that is stored lowercased persists a value the pattern rejects. The fix case-folds the value at the start of apply_constraints/2, so the constraints are checked against the form that is actually stored. This issue affects ash: from 1.29.0-rc0 before 3.32.2.
Affected products (as reported)
| Vendor | Product | Versions |
|---|---|---|
| ash-project | ash | 1.29.0-rc0 – before 3.32.2 |
| ash-project | ash | f6f5d194bfc7802bd32e48bf2eabd2d97a0109a4 – before d8320b0127c8ef453679d70e5dd23a9506951d21 |
Weakness: CWE-180 · Vector: CVSS:4.0/AV:L/AC:L/AT:P/PR:N/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N