Ash field policies do not filter-nil forbidden calculations and aggregates, enabling an information-disclosure oracle

Summary

CVE	CVE-2026-86338
State	PUBLISHED
Assigner	EEF
Source Priority	CVE Program / NVD first with legacy fallback
Published	2026-09-16 09:17:06 UTC
Updated	2026-09-16 20:38:33 UTC
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.

Risk And Classification

Primary CVSS: v4.0 6 MEDIUM from 6b3ad84c-e1a6-4bf7-a703-f496b71e49db

CVSS:4.0/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

EPSS: 0.003210000 probability, percentile 0.251760000 (date 2026-09-16)

Problem Types: CWE-1220 | CWE-1220 CWE-1220 Insufficient Granularity of Access Control

Version	Source	Type	Score	Severity	Vector
4.0	6b3ad84c-e1a6-4bf7-a703-f496b71e49db	Secondary	6	MEDIUM	`CVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N/E:X/C...`
4.0	CNA	CVSS	6	MEDIUM	`CVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N`

CVSS v4.0 Breakdown

Attack Vector

Network

Attack Complexity

Low

Attack Requirements

Present

Privileges Required

Low

User Interaction

None

Confidentiality

High

Integrity

None

Availability

None

Sub Conf.

None

Sub Integrity

None

Sub Availability

None

CVSS:4.0/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

Vendor Declared Affected Products

Source	Vendor	Product	Version	Platforms
CNA	Ash-project	Ash	affected 2.11.0-rc.0 3.33.4 semver	Not specified
CNA	Ash-project	Ash	affected 0b6d93c7c4637280b46ae66ea1d2eaf013701238 b3d4503241f3deacb5ceb955e10a4fa927da0f67 git	Not specified

References

Reference	Source	Link	Tags
cna.erlef.org/cves/CVE-2026-86338.html	6b3ad84c-e1a6-4bf7-a703-f496b71e49db	cna.erlef.org
github.com/ash-project/ash/security/advisories/GHSA-7qr8-wrvq-566q	6b3ad84c-e1a6-4bf7-a703-f496b71e49db	github.com
osv.dev/vulnerability/EEF-CVE-2026-86338	6b3ad84c-e1a6-4bf7-a703-f496b71e49db	osv.dev
github.com/ash-project/ash/commit/0b6d93c7c4637280b46ae66ea1d2eaf013701238	6b3ad84c-e1a6-4bf7-a703-f496b71e49db	github.com
github.com/ash-project/ash/commit/b3d4503241f3deacb5ceb955e10a4fa927da0f67	6b3ad84c-e1a6-4bf7-a703-f496b71e49db	github.com
CVE Program record	CVE.ORG	www.cve.org	canonical
NVD vulnerability detail	NVD	nvd.nist.gov	canonical, analysis

Vendor Comments And Credit

Discovery Credit

CNA: Jesse Williams (en)

CNA: Zach Daniel / Ash Project (en)

CNA: Jonatan Männchen / EEF (en)

CNA: Jesse Williams (en)

There are currently no legacy QID mappings associated with this CVE.