CVE-2026-82736

Ash.Type.CiString validates length and match constraints before case folding, allowing constraint bypass

LOW
2.1
CVSS Score
Published: September 1, 2026 at 03:21 AM UTC
Updated: September 1, 2026 at 09:31 PM UTC
1 product affected across 1 vendorAsh

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Severity
LOW2.1
Exploit prediction
EPSS 0.2%
SSVC
PoC

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

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

90%
1.29.0-rc0 ≤ v < 3.32.21.29.0-rc0f6f5d194bfc7802bd32e48bf2eabd2d97a0109a4
Vendor states this is fixed in d8320b0127c8ef453679d70e5dd23a9506951d21 (fixed)
Affected range stops below 3.32.2, so it looks safe — our inference, not a vendor statement

Remediation

No guide yet

No remediation guidance has been written for this CVE yet. What the record does show:

SSVC — Action Prioritization

SSVCPoCNot automatablePartial impact

SSVC signals action urgency (what to patch first), separate from CVSS which measures severity.

CVSS

2.1LOWEEF
Vector?

Quick Info

StatusDEFERRED
CWE
CWE-180

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