# CVE-2026-116672: Authlib RFC 7592 examples omit registration-access-token client binding


- **Severity:** High 8.8 (`CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H`)
- **Exploited in the wild:** Not known
- **Fix available:** No
- **Published:** 27 Oct 2026
- **Updated:** 27 Oct 2026
- **Also known as:** DEBIAN-CVE-2026-116672, GHSA-c73q-w75p-j82v, UBUNTU-CVE-2026-116672

## What is CVE-2026-116672?

CVE-2026-116672 is a high-severity vulnerability in authlib, published on 27 Oct 2026. 

### Official description

Authlib is a Python library which builds OAuth and OpenID Connect servers. From 0.15 until 1.9.1, the documented ClientConfigurationEndpoint.authenticate_client and ClientConfigurationEndpoint.check_permission reference implementations look up a target client from request-controlled client_id data and check only whether that target is editable, without verifying that request.credential belongs to the target client. Deployments following both examples can allow a client holding any valid registration access token to read, modify, or delete another client's registration. Changing redirect_uris can enable authorization code or token interception, while deleting registrations can deny service to affected clients. This issue is fixed in version 1.9.1.

Weakness: CWE-639 (Authorization Bypass Through User-Controlled Key), CWE-1188 (Initialization of a Resource with an Insecure Default)

## Which versions are affected by CVE-2026-116672?


## How do I fix CVE-2026-116672?

No fix has been published for CVE-2026-116672 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-116672 being exploited?

There is no known exploitation of CVE-2026-116672 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-116672 and fix it if it is affected.

What it is: CVE-2026-116672 is a high-severity vulnerability in authlib, published on 27 Oct 2026. 
Exploitation: There is no known exploitation of CVE-2026-116672 in the wild and no public exploit code.

Affected product: authlib. No package-level version data is available, so check the vendor advisory linked from the reference page.

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-2026-116672/ (Markdown: https://insights.sbomify.com/CVE-2026-116672/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-116672
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-116672
- OSV: https://osv.dev/vulnerability/CVE-2026-116672

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From sbomify Insights: https://insights.sbomify.com/CVE-2026-116672/
Summaries are generated and may contain mistakes; the official description above is the record.