---
id: CVE-2026-78699
title: >-
  Unchecked Return Value vulnerability in ash-project ash_postgres allows a user
  who can drive a tenant rename to a name that collides with an existing
  tenant's schema to have their tenant record repointed at that other tenant's
  live schem…
summary: >-
  Unchecked Return Value vulnerability in ash-project ash_postgres allows a user
  who can drive a tenant rename to a name that collides with an existing
  tenant's schema to have their tenant record repointed at that other tenant's
  live schem…
severity: none
cwe:
  - CWE-252
published: '2026-08-30'
updated: '2026-08-30'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-78699'
references:
  - url: 'https://cna.erlef.org/cves/CVE-2026-78699.html'
    label: 6b3ad84c-e1a6-4bf7-a703-f496b71e49db
  - url: >-
      https://github.com/ash-project/ash_postgres/commit/8544ab15fe45784553c2d2da8ee1a388eee0174b
    label: 6b3ad84c-e1a6-4bf7-a703-f496b71e49db
  - url: >-
      https://github.com/ash-project/ash_postgres/security/advisories/GHSA-6fqq-j9c4-5766
    label: 6b3ad84c-e1a6-4bf7-a703-f496b71e49db
  - url: 'https://osv.dev/vulnerability/EEF-CVE-2026-78699'
    label: 6b3ad84c-e1a6-4bf7-a703-f496b71e49db
tags:
  - nvd
ingestedAt: '2026-08-31T01:00:16.555Z'
epss: 0.00113
epssPercentile: 0.01614
---

## Overview

Unchecked Return Value vulnerability in ash-project ash_postgres allows a user who can drive a tenant rename to a name that collides with an existing tenant's schema to have their tenant record repointed at that other tenant's live schema, gaining access to its data.

AshPostgres.MultiTenancy.rename_tenant/3 issues the ALTER SCHEMA ... RENAME TO ... with the non-raising Ecto.Adapters.SQL.query/2, discards its {:ok, _} | {:error, _} result, and unconditionally returns :ok. PostgreSQL rejects the rename when the target schema already exists (and on insufficient privilege or lock timeout), but that failure never reaches the caller. The calling manage_tenant update action therefore sees success and commits the tenant row with the new name, which is the schema of a different existing tenant, so subsequent reads and writes for that tenant run against the other tenant's data.

This issue affects ash_postgres: from 0.25.0 before 2.13.0.

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.