EEF-CVE-2026-82747 CVE-2026-82747 GHSA-4259-gvr2-4xhq
Ash.Policy.Authorizer returns records denied by a runtime read policy to any actor
- Severity
- 0.0 / 10
- Unknown · CVSS 4.0
- Exploit chance (EPSS)
- 0.17%
- Chance of exploitation in the next 30 days. Higher than 6.42% of scored vulnerabilities.
- Known exploited
- No
- Not in CISA's catalog
- Weakness
- CWE-863 Incorrect Authorization
- Fix
3.32.2- Upgrade ash to this version or later
Description
Summary
Incorrect Authorization vulnerability in ash-project ash returns records that a runtime read policy denies to any actor.
When a resource has an access_type :runtime read policy (a check evaluated per record rather than compiled to a filter), Ash.Policy.Authorizer decides each record in check_result/1 (lib/ash/policy/authorizer/authorizer.ex) by discarding impossible policy scenarios and inspecting what remains. When every scenario for a record was impossible, meaning no policy can authorize it and it must be forbidden, the empty-scenario branch instead kept the record ({[record | data], authorizer, any_forbidden?}) and returned it as authorized. As a result, records the runtime read policy denies are returned to any actor. The fix forbids a record whose scenarios are all impossible.
This issue affects ash: from 3.4.44 before 3.32.2.
Affected versions
Hex
| Package | Vulnerable | Fixed in |
|---|---|---|
| ash | >= 3.4.44, < 3.32.2 |
3.32.2 |
How to fix
Move to the fixed version or later with your package manager, update the lockfile, and run your tests. If the package only arrives through another dependency, upgrade that dependency first. If none of its releases pulls a fixed version yet, force the version with your package manager's override.
ash Hex → 3.32.2
- mix
{:ash, "~> 3.32.2"} # then: mix deps.update ash
Severity breakdown
CVSS 4.0 0.0
CVSS:4.0/AV:L/AC:L/AT:P/PR:N/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N
- Attack vector
- Local
- Attack complexity
- Low
- Attack requirements
- Present
- Privileges required
- None
- User interaction
- None
- Confidentiality (vulnerable system)
- High
- Integrity (vulnerable system)
- None
- Availability (vulnerable system)
- None
- Confidentiality (subsequent systems)
- None
- Integrity (subsequent systems)
- None
- Availability (subsequent systems)
- None
Weakness
CWE-863: Incorrect Authorization
The product performs an authorization check when an actor attempts to access a resource or perform an action, but it does not correctly perform the check.
How to prevent it
- Architecture and Design: Divide the product into anonymous, normal, privileged, and administrative areas. Reduce the attack surface by carefully mapping roles with data and functionality. Use role-based access control (RBAC) [REF-229] to enforce the roles at the appropriate boundaries. Note that this approach may not protect against horizontal authorization, i.e., it will not protect a user from attacking others with the same role.
- Architecture and Design: Ensure that access control checks are performed related to the business logic. These checks may be different than the access control checks that are applied to more generic resources such as files, connections, processes, memory, and database records. For example, a database may restrict access for medical records to a specific database user, but each record might only be intended to be accessible to the patient and the patient's doctor [REF-7].
- Architecture and Design: Use a vetted library or framework that does not allow this weakness to occur or provides constructs that make this weakness easier to avoid. For example, consider using authorization frameworks such as the JAAS Authorization Framework [REF-233] and the OWASP ESAPI Access Control feature [REF-45].
- Architecture and Design: For web applications, make sure that the access control mechanism is enforced correctly at the server side on every page. Users should not be able to access any unauthorized functionality or information by simply requesting direct access to that page. One way to do this is to ensure that all pages containing sensitive information are not cached, and that all such pages restrict access to requests that are accompanied by an active and authenticated session token associated with a user who has the required permissions to access that page.
- System Configuration, Installation: Use the access control capabilities of your operating system and server environment and define your access control lists accordingly. Use a "default deny" policy when defining these ACLs.
References
Advisories
Fixes and patches
Packages
Other links
Timeline
- Published
- Last updated by the source
- Latest EPSS score
Related advisories
| Advisory | Severity | Why it's related |
|---|---|---|
| EEF-CVE-2026-96581 An upsert on the primary key in Ash ignores attribute multitenancy, so one tenant can read, overwrite and take over another tenant's records | Not rated yet | Also affects ash |
| EEF-CVE-2026-114214 Loading a through relationship with a limit of 1 in Ash ignores the through path and returns unrelated destination records | Not rated yet | Also affects ash |
| EEF-CVE-2026-101028 Ash.count, Ash.exists and Ash.aggregate skip related resources' read policies in filters and sorts | Not rated yet | Also affects ash |
| EEF-CVE-2026-94201 Filtering an :atom attribute with unsafe_to_atom? can exhaust the BEAM atom table in Ash | Not rated yet | Also affects ash |
| EEF-CVE-2026-93477 Private action arguments can be set by user input on the bulk destroy and bulk update paths in Ash | Not rated yet | Also affects ash |
| EEF-CVE-2026-86338 Ash field policies do not filter-nil forbidden calculations and aggregates, enabling an information-disclosure oracle | Not rated yet | Also affects ash |
| EEF-CVE-2026-82752 Ash string length constraints count graphemes, so a combining-mark string of any size passes max_length | Not rated yet | Also affects ash |
| EEF-CVE-2026-82749 Ash relationship parent(...) filter degrades to an IS NULL match when the parent field is unresolved, leaking scoped records | Not rated yet | Also affects ash |
Credits: Jonatan Männchen / EEF, Peter Ullrich, Zach Daniel / Ash Project
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