CVE-2026-86338
Vulnérabilité moyenne dans ash (ash-project)
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.
Gravité et risque d'exploitation
CVE-2026-86338 obtient un score CVSS de 6.0/10, soit une gravité moyenne. Selon le modèle EPSS, la probabilité qu'elle soit exploitée dans les 30 prochains jours est de 0.43 %, ce qui la place devant 35.6 % des CVE référencées.
Que faire ?
- Vérifiez si ash (versions 0b6d93c7c4637280b46ae66ea1d2eaf013701238, <b3d4503241f3deacb5ceb955e10a4fa927da0f67, <3.33.4, 2.11.0-rc.0) est présent sur votre parc.
- Appliquez le correctif ou la version corrigée indiqués dans les références de l'éditeur.
- À défaut de correctif, limitez l'exposition (filtrage réseau, désactivation du composant).
- Automatisez la détection : les agents CVE Heimdall (gratuits, open source) corrèlent l'inventaire de vos serveurs avec la base CVE.
Références
- https://github.com/ash-project/ash/security/advisories/GHSA-7qr8-wrvq-566q
- https://cna.erlef.org/cves/CVE-2026-86338.html
- https://osv.dev/vulnerability/EEF-CVE-2026-86338
- https://github.com/ash-project/ash/commit/0b6d93c7c4637280b46ae66ea1d2eaf013701238
- https://github.com/ash-project/ash/commit/b3d4503241f3deacb5ceb955e10a4fa927da0f67