CriticalCVE-2026-86533

    Team-alembic Ash Authentication: Insufficient Session Expiration (CVE-2026-86533)

    Published Last modified Sources: CVE.org, OSV

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    What is affected, what to do

    Insufficient Session Expiration vulnerability in team-alembic AshAuthentication and AshAuthentication Phoenix allows a revoked session to remain fully authenticated. A resource configured with session_identifier :jti and require_token_presence_for_authentication? disabled stores its session value as <jti>:<subject>.

    Update Team-alembic Ash Authentication to version 4.15.0, Team-alembic Ash Authentication to version 5.0.0-rc.14, Team-alembic Ash Authentication Phoenix to version 2.17.4.

    Affected
    • Team-alembic Ash Authentication lt 4.9.1..4.15.0
    • Team-alembic Ash Authentication lt 5.0.0-rc.0..5.0.0-rc.14
    • Team-alembic Ash Authentication Phoenix lt 2.10.0..2.17.4
    • Team-alembic Ash Authentication Phoenix lt 3.0.0-rc.0..3.0.0-rc.11
    Fixed in
    • Team-alembic Ash Authentication 4.15.0
    • Team-alembic Ash Authentication 5.0.0-rc.14
    • Team-alembic Ash Authentication Phoenix 2.17.4
    • Team-alembic Ash Authentication Phoenix 3.0.0-rc.11

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

    Metrics

    9.1

    Priority

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

    Source: Vendor (CNA), CVSS v4

    9.1

    CVSS v4

    Severity Critical on the scale from 0 to 10.

    Source: CVE.org, OSV

    0.9 %

    EPSS score

    Low — model estimates < 1% exploitation likelihood.

    Source: FIRST EPSS, percentile 60.1

    Show all metrics
    Severity
    Critical
    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
    100.60 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
    9.1 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
    9.1
    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
    0.9 %
    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
    60.1
    High — this CVE ranks above the median of all CVEs scored today (rank ≥ 36%).
    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 · automatable · Technical impact: total
    Source: CISA Vulnrichment, as of 17 September 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-613

    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

    Insufficient Session Expiration vulnerability in team-alembic AshAuthentication and AshAuthentication Phoenix allows a revoked session to remain fully authenticated. A resource configured with session_identifier :jti and require_token_presence_for_authentication? disabled stores its session value as <jti>:<subject>. The jti is there so that signing out can revoke that one session. Neither reader consults it: AshAuthentication.Plug.Helpers.authenticate_resource_from_session/4 and AshAuthentication.Phoenix.LiveSession.on_mount/4 both split the value with split_identifier/2, discard the jti and pass the bare subject to AshAuthentication.subject_to_user/3, which reloads the record. The token-presence branch of each function does check its token, calling AshAuthentication.TokenResource.Actions.get_token/3 with the jti and the purpose user. Because the revocation record is never read, neither its revoked state nor its expiry constrains the session, so a session captured before sign-out keeps working. This issue affects ash_authentication: from 4.9.1 before 4.15.0 and from 5.0.0-rc.0 before 5.0.0-rc.14; ash_authentication_phoenix: from 2.10.0 before 2.17.4 and from 3.0.0-rc.0 before 3.0.0-rc.11.

    Source: NVD (NIST), cvelistv5, 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
    team-alembicash_authentication
    • 4.9.1 – < 4.15.0
    • 5.0.0-rc.0 – < 5.0.0-rc.14
    • 4.15.0
    • 5.0.0-rc.14
    team-alembicash_authentication_phoenix
    • 2.10.0 – < 2.17.4
    • 3.0.0-rc.0 – < 3.0.0-rc.11
    • 2.17.4
    • 3.0.0-rc.11
    hexash_authentication
    • 4.13.2
    • 4.9.6
    • 4.9.9
    • 4.14.2
    • 4.13.5
    • 5.0.0-rc.5
    • 5.0.0-rc.7
    • 5.0.0-rc.6
    • 4.14.1
    • 4.9.1
    • 5.0.0-rc.3
    • 5.0.0-rc.4
    • 4.13.7
    • 5.0.0-rc.12
    • 4.9.5
    • 4.13.0
    • 4.13.6
    • 4.10.0
    • 5.0.0-rc.8
    • 4.12.0
    • 4.13.1
    • 4.9.2
    • 5.0.0-rc.13
    • 5.0.0-rc.0
    • 5.0.0-rc.9
    • 4.9.7
    • 4.13.4
    • 5.0.0-rc.10
    • 4.9.8
    • 4.14.0
    • 4.13.3
    • 4.9.4
    • 5.0.0-rc.2
    • 5.0.0-rc.11
    • 4.9.3
    • 5.0.0-rc.1
    • 4.11.0
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    hexash_authentication_phoenix
    • 2.16.0
    • 2.13.0
    • 2.17.3
    • 2.10.1
    • 2.10.3
    • 3.0.0-rc.9
    • 2.12.0
    • —
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    Vendors and products

    Weakness classes (CWE)

    • CWE-613Insufficient Session Expiration

      Base

      According to WASC, "Insufficient Session Expiration is when a web site permits an attacker to reuse old session credentials or session IDs for authorization."

      Entry at MITRE CWE-613

    References & sources

    • github.comteam-alembic/ash_authentication_phoenix/security/advisories/GHS…Vendor advisory, related
    • cna.erlef.orgEEF CNA record for CVE-2026-86533related
    • OSV (Open Source Vulnerabilities)OSV record EEF-CVE-2026-86533related
    • github.comteam-alembic/ash_authentication/security/advisories/GHSA-w374-h…related, Vendor advisory
    • github.comIntroducing commit fcaeb73 in team-alembic/ash_authenticationrelated
    • github.comFix commit a3f49f7 in team-alembic/ash_authenticationPatch
    • github.comFix commit e28e911 in team-alembic/ash_authenticationPatch
    • github.comIntroducing commit a3253fb in team-alembic/ash_authentication_phoenixrelated
    • github.comIntroducing commit 0135217 in team-alembic/ash_authentication_phoenixrelated
    • github.comFix commit f7ab005 in team-alembic/ash_authentication_phoenixPatch
    • hex.pmpackages/ash_authenticationpackage
    • hex.pmpackages/ash_authentication_phoenixpackage

    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: yes

      Show the original change
      Individual changes of this event as published by NVD
      TypeActionBeforeAfter
      SSVC assessmentadded
      —
      {"id":"CVE-2026-86533","role":"CISA Coordinator","options":[{"exploitation":"none"},{"automatable":"yes"},{"technicalImpact":"total"}],"version":"2.0.3","timestamp":"2026-09-17T18:13:50.422619Z"}

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

    2. ReceivedEEF

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

      Weakness type: CWE-613

      Description added or changed

      Show 14 original changes
      Individual changes of this event as published by NVD
      TypeActionBeforeAfter
      Descriptionadded
      —
      Insufficient Session Expiration vulnerability in team-alembic AshAuthentication and AshAuthentication Phoenix allows a revoked session to remain fully authenticated. A resource configured with session_identifier :jti and require_token_presence_for_authentication? disabled stores its session value as <jti>:<subject>. The jti is there so that signing out can revoke that one session. Neither reader consults it: AshAuthentication.Plug.Helpers.authenticate_resource_from_session/4 and AshAuthentication.Phoenix.LiveSession.on_mount/4 both split the value with split_identifier/2, discard the jti and pass the bare subject to AshAuthentication.subject_to_user/3, which reloads the record. The token-presence branch of each function does check its token, calling AshAuthentication.TokenResource.Actions.get_token/3 with the jti and the purpose user. Because the revocation record is never read, neither its revoked state nor its expiry constrains the session, so a session captured before sign-out keeps working. This issue affects ash_authentication: from 4.9.1 before 4.15.0 and from 5.0.0-rc.0 before 5.0.0-rc.14; ash_authentication_phoenix: from 2.10.0 before 2.17.4 and from 3.0.0-rc.0 before 3.0.0-rc.11.
      CVSSadded
      —
      AV:N/AC:L/AT:P/PR:N/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-613
      Affected versions (publisher)added
      —
      New affected value received. <a href="https://github.com/CVEProject/cvelistV5/blob/main/cves/2026/86xxx/CVE-2026-86533.json">CVE-2026-86533</a>
      Referenceadded
      —
      https://cna.erlef.org/cves/CVE-2026-86533.html
      Referenceadded
      —
      https://github.com/team-alembic/ash_authentication/commit/a3f49f758f013d2ff086dd9c5ef2d94e921711b4
      Referenceadded
      —
      https://github.com/team-alembic/ash_authentication/commit/e28e911caa9728d76329afdb0fb26742ffe4eeef
      Referenceadded
      —
      https://github.com/team-alembic/ash_authentication/commit/fcaeb73f76f8f2e9aef8bf637690d2a20dd97596
      Referenceadded
      —
      https://github.com/team-alembic/ash_authentication/security/advisories/GHSA-w374-hvrx-66hg
      Referenceadded
      —
      https://github.com/team-alembic/ash_authentication_phoenix/commit/0135217e34e621dac79ae3d9559aeee49304b0aa
      Referenceadded
      —
      https://github.com/team-alembic/ash_authentication_phoenix/commit/a3253fb4fc7145aeb403537af1c24d3a8d51ffb1
      Referenceadded
      —
      https://github.com/team-alembic/ash_authentication_phoenix/commit/f7ab005a2aac09707a25521653c94893d328cc52
      Referenceadded
      —
      https://github.com/team-alembic/ash_authentication_phoenix/security/advisories/GHSA-m6x4-4gvp-xwjr
      Referenceadded
      —
      https://osv.dev/vulnerability/EEF-CVE-2026-86533

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

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