Insufficient Session Expiration vulnerability in team-alembic AshAuthentication and…
CVE-2026-86533 is a critical-severity vulnerability in ash_authentication from Team-alembic, with a CVSS 4.0 base score of 9.1 out of 10. It can be exploited remotely over the network by an unauthenticated attacker, without any action from a user. The record lists versions 4.15.0, 5.0.0-rc.14 as the first without the flaw, so updating ash_authentication to one of those releases or later removes the exposure. There is no confirmed exploitation so far. EPSS estimates a 0.91% chance of exploitation within 30 days, higher than 60% of scored CVEs.
Critical severity: a successful attack would have severe impact.
What to do
- Update ash_authentication to 4.15.0 or 5.0.0-rc.14, whichever matches your release line, or a later version.
- Update ash_authentication_phoenix to 2.17.4 or 3.0.0-rc.11, whichever matches your release line, or a later version.
- Read the advisory on github.com for workarounds and exact fixed builds.
- Until you can update, restrict network access to the affected service so it is not reachable from untrusted networks.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| Team-alembic | ash_authentication | 4.9.1 up to, but not including, 4.15.0; 5.0.0-rc.0 up to, but not including, 5.0.0-rc.14; fcaeb73f76f8f2e9aef8bf637690d2a20dd97596 and later | 4.15.0, 5.0.0-rc.14 |
| Team-alembic | ash_authentication_phoenix | 2.10.0 up to, but not including, 2.17.4; 3.0.0-rc.0 up to, but not including, 3.0.0-rc.11; a3253fb4fc7145aeb403537af1c24d3a8d51ffb1 and later; 0135217e34e621dac79ae3d9559aeee49304b0aa and later | 2.17.4, 3.0.0-rc.11 |
Version data comes from the organisation that assigned the CVE. Confirm against the vendor advisory before deciding you are unaffected.
How the severity score breaks down
- Attack vector
- NetworkCan be exploited remotely over a network, including the internet.
- Attack complexity
- LowNo special conditions are needed; the attack works reliably.
- Attack requirements
- PresentThe target must be in a specific state or configuration for the attack to work.
- Privileges required
- NoneNo account or login is needed.
- User interaction
- NoneNo action by a victim is required.
- Confidentiality (vulnerable system)
- HighSerious loss of confidentiality on the vulnerable system.
- Integrity (vulnerable system)
- HighSerious loss of integrity on the vulnerable system.
- Availability (vulnerable system)
- NoneNo loss of availability on the vulnerable system.
- Confidentiality (other systems)
- NoneNo loss of confidentiality on systems beyond the vulnerable one.
- Integrity (other systems)
- NoneNo loss of integrity on systems beyond the vulnerable one.
- Availability (other systems)
- NoneNo loss of availability on systems beyond the vulnerable one.
Vector: CVSS:4.0/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. Scored by CNA.
Official 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: the CVE record as published by its numbering authority, via NVD and CVE.org.
Timeline
- CVE record published.
- CISA published its SSVC assessment (exploitation: none, automatable: yes, technical impact: total).
- Record last changed materially (score, affected products, status or references).
References
Advisories
Patches and release notes
- github.com/team-alembic/ash_authentication/commit/a3f49f758f013d2ff086dd9c5ef2d94e921711b4
- github.com/team-alembic/ash_authentication/commit/e28e911caa9728d76329afdb0fb26742ffe4eeef
- github.com/team-alembic/ash_authentication/commit/fcaeb73f76f8f2e9aef8bf637690d2a20dd97596
- github.com/team-alembic/ash_authentication_phoenix/commit/0135217e34e621dac79ae3d9559aeee49304b0aa
- github.com/team-alembic/ash_authentication_phoenix/commit/a3253fb4fc7145aeb403537af1c24d3a8d51ffb1
- github.com/team-alembic/ash_authentication_phoenix/commit/f7ab005a2aac09707a25521653c94893d328cc52
Other vulnerabilities in ash_authentication
- 7.6 High severity
- 7.4 High severity
- 9.1 Critical severity
- 9.1 Critical severity
- 9.1 Critical severity
- 9.1 Critical severity
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