# Backstage's scaffolder credential handling may allow unintended GitHub authentication fallback

Advisory record · `GHSA-29gx-h2m3-xw44`

- **Identifiers:** `GHSA-29gx-h2m3-xw44` · `CVE-2026-106462`
- **State:** Confirmed
- **Severity:** CVSS 6.4 Medium
- **Critical:** No
- **Weakness (CWE):** [CWE-441](https://cwe.mitre.org/data/definitions/441.html) · [CWE-863](https://cwe.mitre.org/data/definitions/863.html)
- **Tags:** [Broken access control](https://agentprime.io/advisories/tag/access-control.md) · [CWE-441](https://agentprime.io/advisories/tag/cwe-441.md)
- **Published:** 7 Oct 2026
- **Updated:** 7 Oct 2026
- **Reviewed by a person:** No

Published by the GitHub Advisory Database at 7 Oct 2026, 18:01 UTC. agentprime has not analysed this yet, so whether it affects any app is not known.

## Affected packages

- `@backstage/plugin-scaffolder-backend` (npm): affected `<4.1.0`; fixed in `4.1.0`
- `@backstage/plugin-scaffolder-backend-module-github` (npm): affected `<0.9.13`; fixed in `0.9.13`
- `@backstage/plugin-scaffolder-backend-module-gitlab` (npm): affected `<0.11.10`; fixed in `0.11.10`
- `@backstage/plugin-scaffolder-backend-module-azure` (npm): affected `<0.2.25`; fixed in `0.2.25`
- `@backstage/plugin-scaffolder-backend-module-bitbucket-cloud` (npm): affected `<0.3.10`; fixed in `0.3.10`
- `@backstage/plugin-scaffolder-backend-module-bitbucket-server` (npm): affected `<0.2.25`; fixed in `0.2.25`

## 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

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

- **CISA KEV:** Not listed.
- **EPSS:** 0.0017, the 6th percentile, on 5 Nov 2026: FIRST’s estimate of the chance of exploitation in the next 30 days.

## Timeline

- 31 Oct 2026, 13:33 UTC: [Confirmed by OSV](https://osv.dev/vulnerability/GHSA-29gx-h2m3-xw44)

## Sources

- [GitHub Advisory Database: GHSA-29gx-h2m3-xw44](https://github.com/advisories/GHSA-29gx-h2m3-xw44)
- [OSV: GHSA-29gx-h2m3-xw44](https://osv.dev/vulnerability/GHSA-29gx-h2m3-xw44)
- <https://github.com/backstage/backstage/security/advisories/GHSA-29gx-h2m3-xw44>
- <https://nvd.nist.gov/vuln/detail/CVE-2026-106462>
- <https://github.com/backstage/backstage/commit/6fb2a41ea47da37eafe5ea744050>
- <https://github.com/backstage/backstage/commit/6fb2a41ea47da37eafe5ea744050ef90be6820c0>
- <https://github.com/backstage/backstage>
- <https://github.com/backstage/backstage/releases/tag/v1.54.6>

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-29gx-h2m3-xw44>, 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-29gx-h2m3-xw44/>. Everything for agents: <https://agentprime.io/llms.txt>.