HighCVE-2026-96581

    Ash: Authorization Bypass Through User-Controlled Key (CVE-2026-96581)

    Published Last modified Sources: CVE.org, OSV

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    What is affected, what to do

    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, Ash.Actions.Create (lib/ash/actions/create/create.ex) and Ash.Actions.Create.Bulk (lib/ash/actions/create/bulk.ex) upserted on the primary key, or on an all_tenants? identity, without scoping the conflicting record to the request's tenant.

    Update Ash to version 3.37.2.

    Affected
    • Ash lt 1.22.0..3.37.2
    Fixed in
    • Ash 3.37.2

    Not sure whether and how you are affected? Ask a question about this vulnerability

    Metrics

    7.6

    Priority

    XIEM Effective CVSS: highest available CVSS rating from NVD and vendor data.

    Source: Vendor (CNA), CVSS v4

    7.6

    CVSS v4

    Severity High on the scale from 0 to 10.

    Source: CVE.org, OSV

    0.3 %

    EPSS score

    Low — model estimates < 1% exploitation likelihood.

    Source: FIRST EPSS, percentile 17.6

    Show all metrics
    Severity
    High
    Priority (0–325)

    The priority score is a consolidated metric that condenses several individual signals into a single, action-guiding ranking: technical severity (CVSS), exploitation likelihood (EPSS), known-exploited status (KEV) and the context of the affected asset. The aim is to answer the only truly important question in vulnerability management: what first?

    Read in glossary
    70.48 Methodology
    Exploit maturity

    An exploit is code or a technique that specifically uses a concrete vulnerability to force unintended behaviour — such as executing code or escalating privileges. It is the tool that turns a theoretical flaw into a practical attack.

    Read in glossary
    no public PoC known
    XIEM Effective CVSS

    XIEM® is the tiered managed-security operating model from NEOSEC and a registered trademark of NEOSEC GmbH. It extends classic SIEM — the central collection, normalisation and correlation of security-relevant events — with endpoint forensics, network visibility and deception technology, and consolidates them into three building tiers: Sentry, Orchestrate and Command.

    Read in glossary
    7.6 Methodology
    CVSS v4

    CVSS is the globally established, open standard for assessing the technical severity of a vulnerability on a scale from 0 to 10. It describes how easily a flaw can be exploited and what damage it can cause — but not how likely its actual exploitation is. CVSS and the complementary EPSS deliberately answer different questions.

    Read in glossary
    7.6
    EPSS score

    The EPSS score is the absolute model output for an individual vulnerability: the estimated probability of real-world exploitation within the next 30 days, expressed as a value between 0 and 1 (i.e. 0 % to 100 %). A score of 0.42 means „the model estimates a 42 % chance of real-world exploitation within 30 days“.

    Read in glossary
    0.3 %
    Low — model estimates < 1% exploitation likelihood.
    EPSS percentile

    The EPSS percentile is the relative position of a vulnerability within all EPSS-scored CVEs, expressed as a value between 0 and 1. A percentile of 0.90 means „this CVE has a higher EPSS score than 90 % of all other scored CVEs“. Unlike the EPSS score, it is not a probability — but a positioning within a ranking.

    Read in glossary
    17.6
    Elevated — this CVE ranks above at least 10% of all CVEs scored today.
    KEV status

    The KEV catalogue is a list maintained by the US authority CISA of vulnerabilities for which active exploitation in the wild has been confirmed. It answers not the question „how severe?“ but „is it already being attacked?“ — thereby sharply prioritising patching.

    Read in glossary
    —
    Published
    CISA assessment (SSVC)
    Exploitation: none known · not automatable · Technical impact: total
    Source: CISA Vulnrichment, as of 26 October 2026
    CWE

    CWE is a catalogue of typical weakness types in software and hardware — such as flawed input validation, unsafe memory handling or poor authentication. Where a CVE names a concrete vulnerability in a concrete product, a CWE describes the underlying class of defect.

    Read in glossary
    CWE-639

    Detection rules

    No NEOSEC detection rule is available for this vulnerability yet.

    Classification under NIS2 and CRA

    Rule-based classification from exploitation status and severity. It does not replace a case-by-case assessment.

    NIS2

    NIS2 is EU Directive (EU) 2022/2555 to raise the level of cybersecurity across the Union. It substantially broadens obligations compared with the first NIS directive: more sectors, mandatory risk management, staged reporting duties and personal accountability of senior management.

    Read in glossary
    High technical severity: assess and remediate the vulnerability in vulnerability handling under Art. 21(2)(e) NIS2 and document the decision.
    CRA

    The CRA is EU Regulation (EU) 2024/2847 setting horizontal cybersecurity requirements for „products with digital elements“ — from industrial controllers and software to connected consumer devices. For the first time manufacturers must ensure security across the entire product lifecycle, handle vulnerabilities and provide security updates.

    Read in glossary
    From 11.12.2027, Annex I Part II CRA requires manufacturers of affected products with digital elements to handle vulnerabilities without delay and provide security updates.
    ISO/IEC 27001

    ISO/IEC 27001 is the internationally leading standard for an information security management system (ISMS). It describes a risk-based, process-oriented framework to systematically plan, implement, review and improve information security.

    Read in glossary
    Control A.8.8, management of technical vulnerabilities: assess relevance to your systems, plan remediation and keep evidence.

    Description

    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, Ash.Actions.Create (lib/ash/actions/create/create.ex) and Ash.Actions.Create.Bulk (lib/ash/actions/create/bulk.ex) upserted on the primary key, or on an all_tenants? identity, without scoping the conflicting record to the request's tenant. A caller of a create action with upsert? true 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.

    Source: cvelistv5, NVD (NIST), CVE.org (MITRE), OSV (Open Source Vulnerabilities)

    Affected products

    The following versions are affected. Older releases of the same product line are also vulnerable unless stated otherwise.

    Affected products
    Affected versionsFixed in
    ash-projectash
    • 1.22.0 – < 3.37.2
    • 3.37.2
    hexash
    • 2.0.0-rc.15
    • 3.25.2
    • 2.1.0
    • 3.12.0
    • 3.0.0-rc.6
    • 2.21.14
    • 3.4.49
    • 1.46.10
    • 2.17.10
    • 1.39.5
    • 2.9.10
    • 2.15.9
    • 2.15.1
    • 1.36.22
    • 2.9.4
    • 2.19.12
    • 2.6.30
    • 2.20.1
    • 1.25.6
    • 3.5.19
    • 2.9.28
    • 2.4.15
    • 1.36.12
    • 3.4.59
    • 3.0.0-rc.37
    • 2.21.11
    • 3.20.0
    • 3.19.2
    • 3.4.11
    • 2.4.6
    • 2.9.2
    • 2.18.2
    • 3.2.1
    • 2.15.5
    • 1.50.0
    • 1.34.4
    • 1.41.3
    • 1.26.8
    • 3.30.0
    • 3.0.0-rc.36
    • 3.4.29
    • 3.15.0
    • 2.6.10
    • 3.9.0
    • 3.10.0
    • 1.35.1
    • 3.23.1
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    Vendors and products

    Weakness classes (CWE)

    • CWE-639Authorization Bypass Through User-Controlled Key

      Base

      The system's authorization functionality does not prevent one user from gaining access to another user's data or record by modifying the key value identifying the data.

      Entry at MITRE CWE-639

    References & sources

    • github.comAn upsert on the primary key in Ash ignores attribute multitenancy, so one tenant can read, overwrite and take over another tenant's recordsadvisory, Vendor advisory, related
    • cna.erlef.orgEEF CNA record for CVE-2026-96581web, related
    • github.comIntroducing commit 2333d01 in ash-project/ashweb, related
    • github.comFix commit c9f0cdb in ash-project/ashfix, Patch
    • hex.pmpackages/ashpackage
    • OSV (Open Source Vulnerabilities)OSV record EEF-CVE-2026-96581related

    Changes to this CVE

    Who changed this CVE and when: NVD (analysis, affected products, CVSS), the CVE publisher (CNA) and additional providers such as CISA (ADP).

    1. Record modifiedCISA ADP

      CISA assessment (SSVC): exploitation: none known, automatable: no

      Show the original change
      Individual changes of this event as published by NVD
      TypeActionBeforeAfter
      SSVC assessmentadded
      —
      {"id":"CVE-2026-96581","role":"CISA Coordinator","options":[{"exploitation":"none"},{"automatable":"no"},{"technicalImpact":"total"}],"version":"2.0.3","timestamp":"2026-10-26T14:25:41.244972Z"}

      Source identifier: 134c704f-9b21-4f2e-91b3-4a467353bcc0

    2. ReceivedEEF

      CVSS V4.0: AV:N/AC:L/AT:P/PR:L/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N

      Weakness type: CWE-639

      Description added or changed

      Show 9 original changes
      Individual changes of this event as published by NVD
      TypeActionBeforeAfter
      Descriptionadded
      —
      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, Ash.Actions.Create (lib/ash/actions/create/create.ex) and Ash.Actions.Create.Bulk (lib/ash/actions/create/bulk.ex) upserted on the primary key, or on an all_tenants? identity, without scoping the conflicting record to the request's tenant. A caller of a create action with upsert? true 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.
      CVSSadded
      —
      AV:N/AC:L/AT:P/PR:L/UI:N/VC:H/VI:H/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
      Weakness type (CWE)added
      —
      CWE-639
      Affected versions (publisher)added
      —
      New affected value received. <a href="https://github.com/CVEProject/cvelistV5/blob/main/cves/2026/96xxx/CVE-2026-96581.json">CVE-2026-96581</a>
      Referenceadded
      —
      https://cna.erlef.org/cves/CVE-2026-96581.html
      Referenceadded
      —
      https://github.com/ash-project/ash/commit/2333d01ddf37e5909769a513059b27e3183331c5
      Referenceadded
      —
      https://github.com/ash-project/ash/commit/c9f0cdb31e7c084def05f3f5be69dd7bb7721754
      Referenceadded
      —
      https://github.com/ash-project/ash/security/advisories/GHSA-vw7c-67pf-gh96
      Referenceadded
      —
      https://osv.dev/vulnerability/EEF-CVE-2026-96581

      Source identifier: 6b3ad84c-e1a6-4bf7-a703-f496b71e49db

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