# Revoked session accepted because the session jti is never checked in AshAuthentication and AshAuthentication Phoenix

Advisory record · `GHSA-m6x4-4gvp-xwjr`

- **Identifiers:** `GHSA-m6x4-4gvp-xwjr` · `CVE-2026-86533` · `EEF-CVE-2026-86533`
- **State:** Confirmed
- **Severity:** CVSS 9.1 Critical
- **Critical:** Yes: CVSS 9+
- **Weakness (CWE):** [CWE-613](https://cwe.mitre.org/data/definitions/613.html)
- **Tags:** [Authentication bypass](https://agentprime.io/advisories/tag/auth-bypass.md)
- **Published:** 17 Sept 2026
- **Updated:** 13 Oct 2026
- **Reviewed by a person:** No

Published by the GitHub Advisory Database at 17 Sept 2026, 13:09 UTC. agentprime has not analysed this yet, so whether it affects any app is not known.

## Critical

Critical, because:

- CVSS score 9.1: 9.0 or more.

How we decide what’s critical: <https://agentprime.io/advisories/critical.md>

## Affected packages

- `ash_authentication` (Hex): affected `>=4.9.1, <4.15.0 || >=5.0.0-rc.0, <5.0.0-rc.14`; fixed in `4.15.0`, `5.0.0-rc.14`
- `ash_authentication_phoenix` (Hex): affected `>=2.10.0, <2.17.4 || >=3.0.0-rc.0, <3.0.0-rc.11`; fixed in `2.17.4`, `3.0.0-rc.11`

## Not analysed yet

We haven’t published our analysis of this Advisory yet. Once a person has reviewed it, this page will say what’s vulnerable, what has to be true for your app to be affected, and how to check.

## Severity and exploitation

- 9.1 Critical, CVSS 4.0: `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`, from CNA (EEF)

- **CISA KEV:** Not listed.
- **EPSS:** 0.0091, the 60th percentile, on 5 Nov 2026: FIRST’s estimate of the chance of exploitation in the next 30 days.

## Timeline

- 31 Oct 2026, 15:25 UTC: First seen by agentprime
- 31 Oct 2026, 15:25 UTC: [Confirmed by OSV](https://osv.dev/vulnerability/EEF-CVE-2026-86533)

## Sources

- [GitHub Advisory Database: GHSA-m6x4-4gvp-xwjr](https://github.com/advisories/GHSA-m6x4-4gvp-xwjr)
- [OSV: GHSA-m6x4-4gvp-xwjr](https://osv.dev/vulnerability/GHSA-m6x4-4gvp-xwjr)
- <https://github.com/team-alembic/ash_authentication_phoenix/security/advisories/GHSA-m6x4-4gvp-xwjr>
- <https://cna.erlef.org/cves/CVE-2026-86533.html>
- <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>
- <https://hex.pm/packages/ash_authentication>
- <https://hex.pm/packages/ash_authentication_phoenix>

Facts on this page come from the GitHub Advisory Database (CC-BY 4.0), OSV and the other sources listed, as published. We don’t reproduce full advisory descriptions, which can contain exploit code.

## Check whether this affects you

A Match means an installed version is in the affected range above. Most don’t affect the app; agentprime hasn’t analysed this one yet.

- With the agentprime MCP server (<https://api.agentprime.io/mcp>), ask your agent to check the project: `check_lockfile` sends a lockfile, `check_packages` a list of installed packages, and both return the Matches and the upgrades that clear them. `get_advisory` returns this record. Setup: <https://agentprime.io/mcp.md>
- In a browser: <https://agentprime.io/check/> reads your lockfile in the browser, never uploading it.
- Whether it touches your code, with file and line: the Claude Code plugin, <https://agentprime.io/plugin.md>
- As JSON: <https://api.agentprime.io/v1/advisories/GHSA-m6x4-4gvp-xwjr>, or `POST https://api.agentprime.io/v1/match` with your packages (<https://agentprime.io/api.md>)

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The web page: <https://agentprime.io/advisories/GHSA-m6x4-4gvp-xwjr/>. Everything for agents: <https://agentprime.io/llms.txt>.