CVE-2026-86338

What it is

Ash field_policies are documented to protect against filter-based information disclosure: when a field the actor may not see is referenced in a filter, it is replaced with an expression that evaluates to nil, so a filter cannot be used as a yes/no oracle to read a value the actor cannot see. This nilling was applied to attributes but not to calculations or aggregates. A user-supplied filter reference to a calculation or aggregate carries an Ash.Query.Calculation / Ash.Query.Aggregate struct, which the authorizer's reference replacement did not match (it only matched the Ash.Resource.* structs), so the filter ran against the real value. As a result, an actor whose field policies forbid a calculation or aggregate can still filter by it (for example filter(secret_calc == "x") or filter(comment_count == n)) and learn the value from whether rows match — an oracle that recovers field-policy-protected values one probe at a time. Filtering is commonly exposed to lower-privileged actors (for example via AshGraphql or AshJsonApi filter arguments), which is exactly the surface field policies are meant to protect. The fix routes filter references to calculations and aggregates through the same field-policy nilling as attributes. This issue affects ash: from 2.11.0-rc.0 before 3.33.4.

At a glance

Exploitability

Can be exploited over the network with a low-privilege account. High risk of data exposure.

Exploit odds

0.4% chance of exploitation in the next 30 days (EPSS).

Fix

A patch, advisory or fixed version is referenced. Upgrade or apply it.

Timeline

1. 2026-09-16 09:17 UTC PublishedDisclosed publicly on CVE.org and NVD
2. 2026-09-16 20:38 UTC Last updatedMost recent change to the record

Why it ranks here

• Exploited in the wild: no, CISA does not list it.
• Exploit odds: 0.4% in the next 30 days (EPSS).
• Severity: 6.0 MEDIUM (CVSS).
• Fix: a patch or advisory is linked.

Details

Published

2026-09-16 09:17 UTC

Last modified

2026-09-16 20:38 UTC

Exploit probability

0.4% · EPSS, next 30 days

Weakness

CWE-1220

Record status

Awaiting Analysis

Attack profile CVSS 4.0 · 6.0

Attack vector

Network

Complexity

Low

Attack requirements

Present

Privileges needed

Low

User interaction

None

Confidentiality

High

Integrity

None

Availability

None

Is it in your code?

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