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Vulnerabilities

Vulnerability · CVE-2026-96581

An upsert on the primary key in Ash ignores attribute multitenancy, so one tenant can read, overwrite and take over another tenant's records

Published Oct 26, 2026 · catalog updated Oct 26, 2026 · An upsert on the

Last checked Nov 7, 2026. A connected source was read within the last 7 days.

Check if you run it

No confirmed exploitation is on record for CVE-2026-96581. EPSS is 0.26%. Act only if a listed version of An upsert on the is installed.

Gaps on this record

  • The stored product name is a package slug. The name on this page is taken from the title (An upsert on the).
  • No vendor fix or required action is stored. Compare the linked advisory before you change production.
Severity
Unknown—
Known exploitation
Not in CISA/VulnCheck KEV
EPSS
0.26%
Remediation
Advisory link
Affected products
Hex ash

## Summary Authorization Bypass Through User-Controlled Key vulnerability in ash-project ash allows a user of one tenant to read, overwrite and take over another tenant's records via an upserting create action. Under attribute multitenancy, ( ) and ( ) upserted on the primary key, or on an identity, without scoping the conflicting record to the request's tenant. A caller of a create action with that accepts the primary key, supplying a record id from another tenant, updated that record's upsert fields and received all of its attributes in the result. With the default upsert fields the tenant attribute was written too, moving the record into the caller's tenant. Read and update policies do not run for upserts, and tenant-scoped create policies pass because the tenant is the caller's own. This issue affects ash: from 1.22.0 before 3.37.2. ## Impact A signed-in user of one tenant posts another tenant's record id to an upserting create action, receives that record's attributes, overwrites its upsert fields, and with the default upsert fields moves it into their own tenant. ## Workarounds Add to every create action that upserts on the primary key or on an identity, and do not combine it with . An upsert into another tenant's record then fails with (or is skipped in a bulk create) and leaves that record unchanged. This does not help on the Mnesia data layer, which ignores upsert conditions in affected versions. ## Configurations Reachable when a resource uses attribute multitenancy and exposes to callers of one tenant a create action with that either upserts on the primary key (no ) and accepts it, or upserts on an identity, and the caller knows or can enumerate a key belonging to another tenant (for example a serial integer id, or an id from a shared link or export).

Are you affected?

Enter the version you run. The result uses only the ranges stored on this record.

The check returns affected, not affected, or incomplete. It does not guess a version that is missing from the record.

  • Hex ash1.22.0 → 3.37.2

How to fix CVE-2026-96581

What to do

Three questions, each answered from this record only. Confirm the vendor advisory before you patch.

Should you patch?

No confirmed exploitation is on record for CVE-2026-96581. EPSS is 0.26%. Act only if a listed version of An upsert on the is installed.

Which versions are affected?

Compare what you have installed with 1.22.0 → 3.37.2. Compare the installed version with the linked vendor advisory before you change production.

What should an analyst verify?

CWE-639: Authorization Bypass Through User-Controlled Key. EPSS 0.26%. There is no CISA KEV listing. No Exploit-DB or Metasploit reference is linked. Use the source links for the original advisory.

Code

The project this record applies to. Exploit listings stay in References.

Timeline

Detection, updates, and resolution for this record.

  1. Oct 26, 2026 · GitHub Advisory Database

    Detected

    ## Summary Authorization Bypass Through User-Controlled Key vulnerability in ash-project ash allows a user of one tenant to read, overwrite and take over another tenant's records via an upserting create action. Under attribute multitenancy, ( ) and ( ) upserted on the primary key, or on an identity, without scoping the conflicting record to the request's tenant. A caller of a create action with th

  2. Oct 26, 2026 · GitHub Advisory Database

    Fix available

    ash fixed in 3.37.2

  3. Oct 26, 2026 · GitHub Advisory Database

    Fix available

    ash fixed in 3.37.2

  4. Oct 26, 2026 · GitHub Advisory Database

    Updated

    ## Summary Authorization Bypass Through User-Controlled Key vulnerability in ash-project ash allows a user of one tenant to read, overwrite and take over another tenant's records via an upserting create action. Under attribute multitenancy, ( ) and ( ) upserted on the primary key, or on an identity, without scoping the conflicting record to the request's tenant. A caller of a create action with th

Sources

References

Freshness

Last verified in this catalog Nov 7, 2026. Significant claims (KEV, EPSS, CVSS, affected ranges) come from the source rows above — open the original publisher for the authoritative advisory.

  • FIRST EPSSNov 7, 2026
  • CVE.orgOct 26, 2026
  • GitHub Advisory DatabaseOct 26, 2026
  • OpenSSF OSV / OSV ScannerOct 26, 2026