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TI-2026-59262 Aliases CVE-2026-86688

Session id is not renewed on authentication in ash_authentication, allowing session fixation

Priority LOW 36CWE-384Published · Updated

Key facts

Attack vector
Network
Privileges required
None
User interaction
Active
Attack complexity
Low
Attack requirements
Present
Impact type
Spoofing
Confidentiality · integrity · availability
High · High · None
Fix status
Fixed

Attack profile from CVSS 4.0 · CNA. Fix status from CNA. Impact type from CWE-384.

Summary

Session Fixation vulnerability in team-alembic ash_authentication allows an attacker who can plant a session identifier in a victim's browser to hold an authenticated session once that victim signs in. AshAuthentication.Plug.Helpers.store_in_session/2 writes the authenticated subject into the existing session with Plug.Conn.put_session/3 and never calls Plug.Conn.configure_session(renew: true), so the identifier the visitor arrived with carries into their authenticated session. Every authentication event reaches this one function: the default success/4 injected by AshAuthentication.Phoenix.Controller.__using__/1, the AuthController emitted by mix ash_authentication_phoenix.install, and remember-me auto-login. AshAuthentication.Phoenix.Plug.store_in_session/2 is a defdelegate to it. Logout does not close the window either, because clear_session/2 ends with Plug.Conn.clear_session/1, which clears session contents but leaves the identifier intact, so a planted identifier survives a logout-then-login cycle. This issue affects ash_authentication: from 0.2.0 before 4.15.0 and from 5.0.0-rc.0 before 5.0.0-rc.14.

Why it matters now

Exploitation None reported CISA SSVC · not in CISA KEV
EPSS 0.00742 54th percentileScored 2026-11-07
Fix Fixed ash_authentication (team-alembic): 4.15.0, 5.0.0-rc.14

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation
None
Automatable
No
Technical impact
Total

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

VendorProductAffected versionsFixed inStatusSource
team-alembicash_authentication0.2.0 to before 4.15.0; 5.0.0-rc.0 to before 5.0.0-rc.144.15.0, 5.0.0-rc.14Patch availableCNA
  • ash_authentication Vendorteam-alembic Affected 0.2.0 to before 4.15.0; 5.0.0-rc.0 to before 5.0.0-rc.14 Fixed in 4.15.0, 5.0.0-rc.14 Patch available CNA

CPE names CNA · 1

CPEVersionsRoleVendor
cpe:2.3:a:team-alembic:ash_authentication:*:*:*:*:*:*:*:*———
  • cpe:2.3:a:team-alembic:ash_authentication:*:*:*:*:*:*:*:* Versions — — ·—

Remediation

  • Fix · CNA ash_authentication (team-alembic) Fixed in 4.15.0, 5.0.0-rc.14

Fixed in the same release

Records fixed by the same vendor advisory or release, as the CNA lists them.

  • Release ·

    team-alembic ash_authentication 4.15.0, 5.0.0-rc.14

    14 records Highest priority Priority MEDIUM 5 MEDIUM, 9 LOW

    Other records, highest priority first

    • TI-2026-59214 Revoked session accepted because the session jti is never checked in AshAuthentication and AshAuthentication PhoenixPriority MEDIUM 49
    • TI-2026-58664 `require_confirmed_with` is not enforced on the action and fails open on an unreadable attribute in AshAuthenticationPriority MEDIUM 49
    • TI-2026-53751 Remember-me sign-in guard reads a session key that is never written in ash_authentication, allowing session replacementPriority MEDIUM 49
    Show all 14 records →

Timeline

  1. 2026-10-02 Threatist record created from CVE-2026-86688

References

Patch 2

Advisory 1

Other 3

  • TI-2026-36668 OAuth2/OIDC account takeover in AshAuthentication via email-based user matching CVSS 4.0CRITICAL 9.2
  • TI-2026-46782 Purpose-limited JWT accepted as full bearer authentication in AshAuthentication CVSS 4.0HIGH 7.6
  • TI-2026-59214 Revoked session accepted because the session jti is never checked in AshAuthentication and AshAuthentication Phoenix CVSS 4.0CRITICAL 9.1
  • TI-2026-58664 `require_confirmed_with` is not enforced on the action and fails open on an unreadable attribute in AshAuthentication CVSS 4.0CRITICAL 9.1
  • TI-2026-53751 Remember-me sign-in guard reads a session key that is never written in ash_authentication, allowing session replacement CVSS 4.0CRITICAL 9.1
  • TI-2026-57079 Magic link single-use tokens replayable via TOCTOU race in AshAuthentication CVSS 4.0CRITICAL 9.1
See all 23 →

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences