CVE-2026-78699
rename_tenant returns :ok on a failed rename, enabling cross-tenant access in AshPostgres
- State
- Published
- Severity
- 7.2 High
- Published
- Aug 30, 2026
- Updated
- Sep 1, 2026
- Reserved
- Aug 30, 2026
Description
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.
Scores
| CVSS | Score | Vector | Source |
|---|---|---|---|
| 4.0 | 7.2 High | 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 | EEF |
Weaknesses
- CWE-252 Unchecked Return Value
Affected Products
| Product | Versions |
|---|---|
ash_postgresash-project |
|
ash_postgresash-project |
|
References
- https://github.com/ash-project/ash_postgres/security/advisories/GHSA-6fqq-j9c4-5766vendor-advisoryrelated
- https://cna.erlef.org/cves/CVE-2026-78699.htmlrelated
- https://osv.dev/vulnerability/EEF-CVE-2026-78699related
- https://github.com/ash-project/ash_postgres/commit/8544ab15fe45784553c2d2da8ee1a388eee0174bpatch
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