NVD / CVE Program· CNA EEF

CVE-2026-86338: Ash field policies do not filter-nil forbidden calculations and aggregates, enabling an information-disclosure oracle

Noroxi assessment

Priority: Monitor (action score 24/100)

The sources we track (CISA KEV, Exploit-DB, Metasploit, Nuclei, GitHub) show no public exploit code or exploitation in the wild.
Probability of exploitation in the next 30 days: 0.42% (FIRST EPSS).
Anyone who can reach it over the internet can trigger it. A low-privileged account is enough. No user action is required. No special conditions are required; it is repeatable.
Fixed version: ash-project ash 3.33.4, b3d4503241f3deacb5ceb955e10a4fa927da0f67.

Low priority for now. Upgrade to ash-project ash 3.33.4, b3d4503241f3deacb5ceb955e10a4fa927da0f67 or later.

Generated automatically from the record's data: CVSS (NVD and CNA), CISA KEV and SSVC, FIRST EPSS, exploit sources, fixed versions. How we calculate it

Primary sources: NVD · CVE.org · FIRST EPSS

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.

MediumCVSS 6.0 · v4.0—No exploit Fix available

Published: Sep 16, 2026
Updated: Sep 16, 2026
EPSS: 0.4% · 37th percentile
CWE: CWE-1220

Report tools

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Action score

Monitor

Low priority for now.

CVSS: 24 / 40 · 6.0 / 10
CISA KEV: 0 / 30 · Not listed
EPSS: 0 / 30 · 0.4%

CISA SSVC decision

Exploitation: none
Automatable: no
Technical impact: partial

Vulnrichment: CISA's decision-tree inputs.

CNA vs NVD score

NVD: —
CNA · EEF: 6.0; NVD has not scored this yet; the score shown is the CNA’s.

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

The score given by the assigning authority versus NVD’s independent score. A gap means the severity is contested.

Get told when this record changes

Not in KEV: no record of exploitation in the wild
No public exploit code on record
A fix has been released

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Noroxi analysis

What does it mean in your environment?

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Affected systems

Is your version affected?

Pick the product and type the version you run. It's compared with this record's version ranges in your browser; the version isn't sent anywhere.

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Versions reported by the vendor

Affected version ranges reported by the assigning authority (EEF). Independent of NVD's CPE analysis and usually ahead of it.

ash-project ash
- 2.11.0-rc.0 and later · before 3.33.4affected · semver
- 0b6d93c7c4637280b46ae66ea1d2eaf013701238 and later · before b3d4503241f3deacb5ceb955e10a4fa927da0f67affected · git

Package-level exposure

OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.

Ecosystem	Package	Affected range	Fix
Hex	ash	from 2.11.0-rc.0 · before 3.33.4	3.33.4

Same product

ash-project: all records

Other highest-scoring records for the same primary product.

CVE-2025-48044Authorization bypass when bypass policy condition evaluates to true
34Monitor
CVE-2025-48043Bypass and runtime policies that can never pass may be incorrectly applied in filter authorization
34Monitor
CVE-2026-94201Filtering an :atom attribute with unsafe_to_atom? can exhaust the BEAM atom table in Ash
32Monitor

Published before and after this one in the same product

← EarlierCVE-2026-82747Sep 1, 2026 · Ash.Policy.Authorizer returns records denied by a runtime read policy to any actor
23Monitor
← EarlierCVE-2026-82752Sep 5, 2026 · Ash string length constraints count graphemes, so a combining-mark string of any size passes max_length
23Monitor
Later →CVE-2026-93477Sep 25, 2026 · Private action arguments can be set by user input on the bulk destroy and bulk update paths in Ash
23Monitor

Remediation

Which version to upgrade to

Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.

Product / package	Fixed version	Source
ash-project ash	3.33.4	Vendor (CNA)
ash-project ash	b3d4503241f3deacb5ceb955e10a4fa927da0f67	Vendor (CNA)
Hex:ash	3.33.4	Package registry (OSV)

Exploit status

No known public exploit

No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.

Research context

For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.

Timeline

From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.

No dated events beyond publication.

EPSS, last 120 days

FIRST EPSS daily score; only changes of 0.01 or more are recorded (step chart).

Patch and commit links

Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.

Credits

All researchers

Finders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.

Zach Daniel / Ash Projectremediation developer
Jesse Williamsreporter
Jonatan Männchen / EEFcoordinator

Variant candidates

Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.

No nightly-computed relations.

Chain candidates

An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.

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Bug bounty scope

No known public program.

Source: bounty-targets-data (public HackerOne, Bugcrowd, Intigriti, YesWeHack listings).

Technical details

Attack conditions

Anyone who can reach it over the internet can trigger it.
A low-privileged account is enough.
No user action is required.
No special conditions are required; it is repeatable.

If successful

Confidentiality
Integrity
Availability

Attack vector: Network
Attack complexity: Low
Privileges required: Low
User interaction: None
Scope: X

Weakness class (CWE)

CWE-1220 · Insufficient Granularity of Access Control

CVSS vector

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

nvd-secondary