# CVE-2026-81632: Single-use sign-in token placed in a redirect query string in AshAuthenticationPhoenix

> Attackers with log access can steal sign-in tokens exposed in redirect URLs, allowing them to authenticate as the victim.

- **Severity:** High 7.2 (`CVSS:4.0/AV:L/AC:L/AT:P/PR:L/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Any signed-in user
- **Attackable:** Local or same network only
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 17 Sep 2026
- **Updated:** 17 Sep 2026
- **Also known as:** EEF-CVE-2026-81632, GHSA-8jh5-339h-mqx9

## What is CVE-2026-81632?

CVE-2026-81632 is a high-severity vulnerability in team-alembic ash_authentication, published on 17 Sep 2026. It can only be exploited from the same machine or local network, with no action from the victim.

### Official description

Use of HTTP Request With Sensitive Query String vulnerability in team-alembic AshAuthenticationPhoenix allows someone able to read access logs, proxy logs or browser history to recover a single-use sign-in token and authenticate as its owner.

After a successful password sign-in, AshAuthentication.Phoenix.Components.Password.SignInForm builds the sign_in_with_token path with the freshly issued user.__metadata__.token as a query parameter and redirects the browser to it with a GET. The token therefore travels in the request line, where web servers, reverse proxies, request telemetry and the browser's own history record it, all of which outlive the request and are ordinarily less protected than session storage. The redirect destination is restricted to a local path, so this is not an open redirect; the exposure is the retention of a live credential.

This issue affects ash_authentication_phoenix: from 1.7.0 before 2.17.4 and from 3.0.0-rc.0 before 3.0.0-rc.11; ash_authentication: from 3.10.5 before 4.15.0 and from 5.0.0-rc.0 before 5.0.0-rc.14.

Weakness: CWE-598 (Use of HTTP Request With Sensitive Query String)

## Which versions are affected by CVE-2026-81632?

2 open source packages ship an affected version, including ash_authentication and ash_authentication_phoenix.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `ash_authentication` | Hex | From 3.10.5 | 4.15.0, 5.0.0-rc.14 |
| `ash_authentication_phoenix` | Hex | From 1.7.0 | 2.17.4, 3.0.0-rc.11 |

## How do I fix CVE-2026-81632?

Upgrade ash_authentication to a fixed version for your release line: 4.15.0 or 5.0.0-rc.14.

## Is CVE-2026-81632 being exploited?

There is no known exploitation of CVE-2026-81632 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-81632 and fix it if it is affected.

What it is: CVE-2026-81632 is a high-severity vulnerability in team-alembic ash_authentication, published on 17 Sep 2026. It can only be exploited from the same machine or local network, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2026-81632 in the wild and no public exploit code.

Affected packages and fixed versions:
- ash_authentication (Hex): affected from 3.10.5; fixed in 4.15.0, 5.0.0-rc.14
- ash_authentication_phoenix (Hex): affected from 1.7.0; fixed in 2.17.4, 3.0.0-rc.11

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-81632/ (Markdown: https://insights.sbomify.com/CVE-2026-81632/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-81632
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-81632
- OSV: https://osv.dev/vulnerability/CVE-2026-81632

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From sbomify Insights: https://insights.sbomify.com/CVE-2026-81632/
Summaries are generated and may contain mistakes; the official description above is the record.