# OAuthLib: Bearer token can be retrieved as long as client knows a valid client ID for device workflow

Advisory record · `GHSA-3jp2-3mrg-2vxc`

- **Identifiers:** `GHSA-3jp2-3mrg-2vxc` · `CVE-2026-49272`
- **State:** Confirmed
- **Severity:** CVSS 8.5 High
- **Critical:** No
- **Weakness (CWE):** [CWE-287](https://cwe.mitre.org/data/definitions/287.html)
- **Tags:** [Authentication bypass](https://agentprime.io/advisories/tag/auth-bypass.md)
- **Published:** 27 Oct 2026
- **Updated:** 5 Nov 2026
- **Reviewed by a person:** No

Published by the GitHub Advisory Database at 27 Oct 2026, 13:30 UTC. agentprime has not analysed this yet, so whether it affects any app is not known.

## Affected packages

- `oauthlib` (PyPI): affected `>=3.3.0, <4.0.1`; fixed in `4.0.1`

## 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

- 8.5 High, CVSS 3.1: `CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:L/I:H/A:N`, from CNA (GitHub_M)

- **CISA KEV:** Not listed.
- **EPSS:** No score.

## Timeline

- 27 Oct 2026, 13:30 UTC: [Confirmed by GitHub Advisory Database](https://github.com/advisories/GHSA-3jp2-3mrg-2vxc)
- 31 Oct 2026, 14:07 UTC: First seen by agentprime
- 31 Oct 2026, 14:07 UTC: [Confirmed by OSV](https://osv.dev/vulnerability/GHSA-3jp2-3mrg-2vxc)
- 5 Nov 2026, 20:58 UTC: [Confirmed by the CVE List](https://www.cve.org/CVERecord?id=CVE-2026-49272)
- 5 Nov 2026, 21:18 UTC: [Confirmed by NVD](https://nvd.nist.gov/vuln/detail/CVE-2026-49272)

## Sources

- [GitHub Advisory Database: GHSA-3jp2-3mrg-2vxc](https://github.com/advisories/GHSA-3jp2-3mrg-2vxc)
- [OSV: GHSA-3jp2-3mrg-2vxc](https://osv.dev/vulnerability/GHSA-3jp2-3mrg-2vxc)
- <https://github.com/oauthlib/oauthlib/security/advisories/GHSA-3jp2-3mrg-2vxc>
- <https://github.com/oauthlib/oauthlib/pull/954>
- <https://github.com/oauthlib/oauthlib/commit/77a5f1c8ce00da2b0b8c5f6e9cc129920085f114>
- <https://github.com/oauthlib/oauthlib>
- <https://github.com/oauthlib/oauthlib/releases/tag/v4.0.1>

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-3jp2-3mrg-2vxc>, 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-3jp2-3mrg-2vxc/>. Everything for agents: <https://agentprime.io/llms.txt>.