6.0
MEDIUM CVSS 4.0
CVE-2026-86338
Ash field policies do not filter-nil forbidden calculations and aggregates, enabling an information-disclosure oracle
Description

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.

INFO

Published Date :

Sept. 16, 2026, 9:17 a.m.

Last Modified :

Sept. 16, 2026, 8:38 p.m.

Remotely Exploit :

Yes !

Source :

6b3ad84c-e1a6-4bf7-a703-f496b71e49db
Affected Products

The following products are affected by CVE-2026-86338 vulnerability. Even if cvefeed.io is aware of the exact versions of the products that are affected, the information is not represented in the table below.

ID Vendor Product Action
1 Ash-project ash
1 Ash-hq ash_framework
CVSS Scores
The Common Vulnerability Scoring System is a standardized framework for assessing the severity of vulnerabilities in software and systems. We collect and displays CVSS scores from various sources for each CVE.
Score Version Severity Vector Exploitability Score Impact Score Source
CVSS 134c704f-9b21-4f2e-91b3-4a467353bcc0
CVSS 4.0 MEDIUM 6b3ad84c-e1a6-4bf7-a703-f496b71e49db
CVSS 4.0 MEDIUM 6b3ad84c-e1a6-4bf7-a703-f496b71e49db
Solution
Apply the security fix by routing filter references through field-policy nilling.
  • Update ash to a version that includes the fix.
  • Ensure all filter references are correctly nill-ed.
References to Advisories, Solutions, and Tools
CWE - Common Weakness Enumeration

While CVE identifies specific instances of vulnerabilities, CWE categorizes the common flaws or weaknesses that can lead to vulnerabilities. CVE-2026-86338 is associated with the following CWEs:

Common Attack Pattern Enumeration and Classification (CAPEC)

Common Attack Pattern Enumeration and Classification (CAPEC) stores attack patterns, which are descriptions of the common attributes and approaches employed by adversaries to exploit the CVE-2026-86338 weaknesses.

We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).

Results are limited to the first 15 repositories due to potential performance issues.

The following list is the news that have been mention CVE-2026-86338 vulnerability anywhere in the article.

The following table lists the changes that have been made to the CVE-2026-86338 vulnerability over time.

Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.

  • CVE Modified by 134c704f-9b21-4f2e-91b3-4a467353bcc0

    Sep. 16, 2026

    Action Type Old Value New Value
    Added SSVC {'id': 'CVE-2026-86338', 'role': 'CISA Coordinator', 'options': [{'exploitation': 'none'}, {'automatable': 'no'}, {'technicalImpact': 'partial'}], 'version': '2.0.3', 'timestamp': '2026-09-16T14:49:09.195379Z'}
  • New CVE Received by 6b3ad84c-e1a6-4bf7-a703-f496b71e49db

    Sep. 16, 2026

    Action Type Old Value New Value
    Added Description 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.
    Added CVSS V4.0 AV:N/AC:L/AT:P/PR:L/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
    Added CWE CWE-1220
    Added Affected New affected value received. <a href="https://github.com/CVEProject/cvelistV5/blob/main/cves/2026/86xxx/CVE-2026-86338.json">CVE-2026-86338</a>
    Added Reference https://cna.erlef.org/cves/CVE-2026-86338.html
    Added Reference https://github.com/ash-project/ash/commit/0b6d93c7c4637280b46ae66ea1d2eaf013701238
    Added Reference https://github.com/ash-project/ash/commit/b3d4503241f3deacb5ceb955e10a4fa927da0f67
    Added Reference https://github.com/ash-project/ash/security/advisories/GHSA-7qr8-wrvq-566q
    Added Reference https://osv.dev/vulnerability/EEF-CVE-2026-86338
EPSS is a daily estimate of the probability of exploitation activity being observed over the next 30 days. Following chart shows the EPSS score history of the vulnerability.