CVE-2026-86338

MEDIUMCVSS 6/10EPSS 0.32%

Last modified

CVE-2026-86338 is a medium-severity vulnerability rated 6/10 on the CVSS scale. 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. EPSS estimates a 0.32% chance of exploitation in the next 30 days.

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.

Metrics

Weakness Enumeration

Affected Software

Source: CNA advisory (CVE.org). NVD analysis pending.

VendorProductVersions
ash-projectash>= 2.11.0-rc.0, < 3.33.4
ash-projectash>= 0b6d93c7c4637280b46ae66ea1d2eaf013701238, < b3d4503241f3deacb5ceb955e10a4fa927da0f67

References

Timeline

Published
Last Modified
Status
Awaiting Analysis

Frequently Asked Questions

What is CVE-2026-86338?
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.
How severe is CVE-2026-86338?
CVE-2026-86338 has a CVSS score of 6/10 (MEDIUM severity). The EPSS model estimates a 0.32% probability of exploitation in the next 30 days.
How do I fix CVE-2026-86338?
Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

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Source: NVD / NIST