---
cve: "CVE-2026-78699"
severity: "HIGH"
cvss: 7.2
epss: "28.2%"
vendor: "ash-project"
kev: false
exploited: false
published: "2026-08-30 16:16:42"
tags: [cve, security, high]
source: tsecurity.de CVE-Dossier
exported: "2026-09-03T07:09:40+02:00"
---

# CVE-2026-78699

> 7.2 HIGH · 🧪 PoC

## Beschreibung

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.

## CVSS-Vektor

```
CVSS:4.0/AV:L/AC:L/AT:P/PR:L/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N
```

| Metrik | Wert | Bewertung |
|---|---|---|
| AV Angriffsvektor | Lokal | good |
| AC Komplexität | Gering | bad |
| PR Privilegien | Gering | warn |
| UI Interaktion | Keine | bad |

## Patch verfügbar (OSV)

- 8544ab15fe45784553c2d2da8ee1a388eee0174b (Commit)

## Referenzen

- <https://github.com/ash-project/ash_postgres/security/advisories/GHSA-6fqq-j9c4-5766>
- <https://cna.erlef.org/cves/CVE-2026-78699.html>
- <https://osv.dev/vulnerability/EEF-CVE-2026-78699>
- <https://github.com/ash-project/ash_postgres/commit/8544ab15fe45784553c2d2da8ee1a388eee0174b>

---
_Exportiert aus dem [tsecurity.de CVE-Dossier](https://tsecurity.de/cve?cve=CVE-2026-78699) · Datenquellen: EUVD (ENISA), NVD, OSV, CISA KEV, FIRST EPSS, Exploit-DB, BSI BITS_