AshPostgres returns another tenant's record for a skipped upsert when return_skipped_upsert? is set
## Summary Incorrect Authorization vulnerability in ash-project ash_postgres allows a user to read another tenant's record through a skipped upsert. When `Ash.bulk_create/4` or a single create runs as an upsert with `return_skipped_upsert?: true` and the upsert is skipped (for example because its `upsert_condition` does not hold), `AshPostgres.DataLayer` reads the existing row back by the upsert identity in `do_bulk_create/3` and `upsert/4`. That lookup did not apply the resource's attribute multitenancy, so on a resource using `strategy :attribute` it could match and return the row of another tenant with the same identity values, exposing its fields to the caller. This issue affects ash_postgres: from 2.6.22 before 2.15.2. ## Impact A user of one tenant whose upsert is skipped receives another tenant's record with the same identity values. ## Configurations Reachable when a resource uses attribute multitenancy, an action performs upserts with `return_skipped_upsert?: true`, and a caller can supply identity values that another tenant also uses.
- Products
- ash_postgres
- Affected versions
- 2.10.0, 2.11.0, 2.12.0, 2.13.0, 2.13.1, 2.14.0, 2.14.1, 2.14.2, 2.14.3, 2.14.4, 2.14.5, 2.15.0, 2.15.1, 2.6.22, 2.6.23, 2.6.24, 2.6.25, 2.6.26, 2.6.27, 2.6.28, 2.6.29, 2.6.30, 2.6.31, 2.6.32, 2.7.0, 2.8.0, 2.9.0, 2.9.1
- Fixed versions
- 2.15.2
- CVEs
- CVE-2026-115635
- Confirmed fixed CVEs
- Not specified
- Updated in this feed
- 1 Nov 2026, 10:26 UTC · Revision 1
Source evidence
AshPostgres returns another tenant's record for a skipped upsert when return_skipped_upsert? is set
core-osv · Original sourcePublished 25 Oct 2026, 19:48 UTC
## Summary Incorrect Authorization vulnerability in ash-project ash_postgres allows a user to read another tenant's record through a skipped upsert. When `Ash.bulk_create/4` or a single create runs as an upsert with `return_skipped_upsert?: true` and the upsert is skipped (for example because its `upsert_condition` does not hold), `AshPostgres.DataLayer` reads the existing row back by the upsert identity in `do_bulk_create/3` and `upsert/4`. That lookup did not apply the resource's attribute multitenancy, so on a resource using `strategy :attribute` it could match and return the row of another tenant with the same identity values, exposing its fields to the caller. This issue affects ash_postgres: from 2.6.22 before 2.15.2. ## Impact A user of one tenant whose upsert is skipped receives another tenant's record with the same identity values. ## Configurations Reachable when a resource uses attribute multitenancy, an action performs upserts with `return_skipped_upsert?: true`, and a caller can supply identity values that another tenant also uses.
osv:EEF-CVE-2026-115635
ash_postgres
Fixed versions: 2.15.2
Complete source record
{
"id": "731b9342bd51f586303b8d56fa58dbd5d8b72324645f7f7dd539cda9f2e6b258",
"url": "https://osv.dev/vulnerability/EEF-CVE-2026-115635",
"method": "structured",
"payload": {
"kind": "advisory",
"title": "AshPostgres returns another tenant's record for a skipped upsert when return_skipped_upsert? is set",
"summary": "## Summary Incorrect Authorization vulnerability in ash-project ash_postgres allows a user to read another tenant's record through a skipped upsert. When `Ash.bulk_create/4` or a single create runs as an upsert with `return_skipped_upsert?: true` and the upsert is skipped (for example because its `upsert_condition` does not hold), `AshPostgres.DataLayer` reads the existing row back by the upsert identity in `do_bulk_create/3` and `upsert/4`. That lookup did not apply the resource's attribute multitenancy, so on a resource using `strategy :attribute` it could match and return the row of another tenant with the same identity values, exposing its fields to the caller. This issue affects ash_postgres: from 2.6.22 before 2.15.2. ## Impact A user of one tenant whose upsert is skipped receives another tenant's record with the same identity values. ## Configurations Reachable when a resource uses attribute multitenancy, an action performs upserts with `return_skipped_upsert?: true`, and a caller can supply identity values that another tenant also uses.",
"evidence": "osv:EEF-CVE-2026-115635",
"products": [
{
"name": {
"value": "ash_postgres",
"evidence": "/affected/0/package/name"
},
"prerequisites": [],
"fixed_versions": [
{
"value": "2.15.2",
"evidence": "/affected/0/ranges"
}
],
"affected_versions": [
{
"value": "2.10.0",
"evidence": "/affected/0/versions"
},
{
"value": "2.11.0",
"evidence": "/affected/0/versions"
},
{
"value": "2.12.0",
"evidence": "/affected/0/versions"
},
{
"value": "2.13.0",
"evidence": "/affected/0/versions"
},
{
"value": "2.13.1",
"evidence": "/affected/0/versions"
},
{
"value": "2.14.0",
"evidence": "/affected/0/versions"
},
{
"value": "2.14.1",
"evidence": "/affected/0/versions"
},
{
"value": "2.14.2",
"evidence": "/affected/0/versions"
},
{
"value": "2.14.3",
"evidence": "/affected/0/versions"
},
{
"value": "2.14.4",
"evidence": "/affected/0/versions"
},
{
"value": "2.14.5",
"evidence": "/affected/0/versions"
},
{
"value": "2.15.0",
"evidence": "/affected/0/versions"
},
{
"value": "2.15.1",
"evidence": "/affected/0/versions"
},
{
"value": "2.6.22",
"evidence": "/affected/0/versions"
},
{
"value": "2.6.23",
"evidence": "/affected/0/versions"
},
{
"value": "2.6.24",
"evidence": "/affected/0/versions"
},
{
"value": "2.6.25",
"evidence": "/affected/0/versions"
},
{
"value": "2.6.26",
"evidence": "/affected/0/versions"
},
{
"value": "2.6.27",
"evidence": "/affected/0/versions"
},
{
"value": "2.6.28",
"evidence": "/affected/0/versions"
},
{
"value": "2.6.29",
"evidence": "/affected/0/versions"
},
{
"value": "2.6.30",
"evidence": "/affected/0/versions"
},
{
"value": "2.6.31",
"evidence": "/affected/0/versions"
},
{
"value": "2.6.32",
"evidence": "/affected/0/versions"
},
{
"value": "2.7.0",
"evidence": "/affected/0/versions"
},
{
"value": "2.8.0",
"evidence": "/affected/0/versions"
},
{
"value": "2.9.0",
"evidence": "/affected/0/versions"
},
{
"value": "2.9.1",
"evidence": "/affected/0/versions"
}
]
}
],
"severity": "medium",
"structured": {
"id": "EEF-CVE-2026-115635",
"aliases": [
"CVE-2026-115635",
"EEF-CVE-2026-115635",
"GHSA-36hg-wwp2-fg8w"
],
"metrics": [
{
"type": "CVSS_V4",
"score": "CVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N"
}
],
"affected": [
{
"ranges": [
{
"type": "SEMVER",
"events": [
{
"introduced": "2.6.22"
},
{
"fixed": "2.15.2"
}
]
}
],
"package": {
"name": "ash_postgres",
"purl": "pkg:hex/ash_postgres",
"ecosystem": "Hex"
},
"versions": [
"2.10.0",
"2.11.0",
"2.12.0",
"2.13.0",
"2.13.1",
"2.14.0",
"2.14.1",
"2.14.2",
"2.14.3",
"2.14.4",
"2.14.5",
"2.15.0",
"2.15.1",
"2.6.22",
"2.6.23",
"2.6.24",
"2.6.25",
"2.6.26",
"2.6.27",
"2.6.28",
"2.6.29",
"2.6.30",
"2.6.31",
"2.6.32",
"2.7.0",
"2.8.0",
"2.9.0",
"2.9.1"
],
"database_specific": {
"source": "https://cna.erlef.org/osv/EEF-CVE-2026-115635.json"
}
},
{
"ranges": [
{
"repo": "https://github.com/ash-project/ash_postgres",
"type": "GIT",
"events": [
{
"introduced": "af0903f1380468bbe1b61fe65acb33772b5e24a5"
},
{
"fixed": "8aa81220c401cae412d21078d11b3519ea25d3a9"
}
]
}
],
"versions": [
"v2.15.1",
"v2.15.0",
"v2.14.5",
"v2.14.4",
"v2.14.3",
"v2.14.2",
"v2.14.1",
"v2.14.0",
"v2.13.1",
"v2.13.0",
"v2.12.0",
"v2.11.0",
"v2.10.0",
"v2.9.1",
"v2.9.0",
"v2.8.0",
"v2.7.0",
"v2.6.32",
"v2.6.31",
"v2.6.30",
"v2.6.29",
"v2.6.28",
"v2.6.27",
"v2.6.26",
"v2.6.25",
"v2.6.24",
"v2.6.23",
"v2.6.22"
],
"database_specific": {
"source": "https://cna.erlef.org/osv/EEF-CVE-2026-115635.json"
}
}
],
"modified": "2026-10-25T20:11:06.333036314Z",
"provider": "osv",
"references": [
"https://github.com/ash-project/ash/security/advisories/GHSA-36hg-wwp2-fg8w",
"https://cna.erlef.org/cves/CVE-2026-115635.html",
"https://github.com/ash-project/ash_postgres/commit/af0903f1380468bbe1b61fe65acb33772b5e24a5",
"https://github.com/ash-project/ash_postgres/commit/8aa81220c401cae412d21078d11b3519ea25d3a9",
"https://hex.pm/packages/ash_postgres"
],
"provider_metadata": {
"cpe_ids": [
"cpe:2.3:a:ash-project:ash_postgres:*:*:*:*:*:*:*:*"
],
"cwe_ids": [
"CWE-863"
],
"capec_ids": [
"CAPEC-1"
]
}
},
"related_cves": [
{
"value": "CVE-2026-115635",
"evidence": "/aliases"
}
],
"security_relevant": true,
"severity_evidence": "/severity/0/score"
},
"source_id": "core-osv",
"document_id": 446220,
"published_at": "2026-10-25T19:48:43.829+00:00"
}