CVE-2026-115635
AshPostgres returns another tenant's record for a skipped upsert when return_skipped_upsert? is set
Description
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.
INFO
Published Date :
Oct. 25, 2026, 8:16 p.m.
Last Modified :
Oct. 25, 2026, 8:16 p.m.
Remotely Exploit :
Yes !
Source :
6b3ad84c-e1a6-4bf7-a703-f496b71e49db
CVSS Scores
| Score | Version | Severity | Vector | Exploitability Score | Impact Score | Source |
|---|---|---|---|---|---|---|
| CVSS 4.0 | MEDIUM | 6b3ad84c-e1a6-4bf7-a703-f496b71e49db | ||||
| CVSS 4.0 | MEDIUM | 6b3ad84c-e1a6-4bf7-a703-f496b71e49db |
Solution
- Update ash_postgres to version 2.15.2 or later.
- Ensure multitenancy is correctly applied to upsert lookups.
- Test the application for unauthorized data access.
- Verify all tenant data remains isolated.
References to Advisories, Solutions, and Tools
Here, you will find a curated list of external links that provide in-depth
information, practical solutions, and valuable tools related to
CVE-2026-115635.
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2026-115635 is
associated with the following CWEs:
Common Attack Pattern Enumeration and Classification (CAPEC)
Common Attack Pattern Enumeration and Classification
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stores attack patterns, which are descriptions of the common attributes and
approaches employed by adversaries to exploit the CVE-2026-115635
weaknesses.
We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).
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CVE-2026-115635 vulnerability anywhere in the article.
The following table lists the changes that have been made to the
CVE-2026-115635 vulnerability over time.
Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.
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New CVE Received by 6b3ad84c-e1a6-4bf7-a703-f496b71e49db
Oct. 25, 2026
Action Type Old Value New Value Added Description 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. Added CVSS V4.0 AV:N/AC:L/AT:P/PR:L/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X Added CWE CWE-863 Added Affected New affected value received. <a href="https://github.com/CVEProject/cvelistV5/blob/main/cves/2026/115xxx/CVE-2026-115635.json">CVE-2026-115635</a> Added Reference https://cna.erlef.org/cves/CVE-2026-115635.html Added Reference https://github.com/ash-project/ash/security/advisories/GHSA-36hg-wwp2-fg8w Added Reference https://github.com/ash-project/ash_postgres/commit/8aa81220c401cae412d21078d11b3519ea25d3a9 Added Reference https://github.com/ash-project/ash_postgres/commit/af0903f1380468bbe1b61fe65acb33772b5e24a5 Added Reference https://osv.dev/vulnerability/EEF-CVE-2026-115635