# CVE-2026-106494: Backstage: Improper input validation in cloud storage URL readers

> An attacker with cloud storage write access can craft object names to overwrite protected files, potentially leading to content injection or code execution.

- **Severity:** Medium 4.4 (`CVSS:3.1/AV:N/AC:H/PR:H/UI:N/S:U/C:N/I:H/A:N`)
- **Exploited in the wild:** Not known
- **Login needed:** An administrator
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 6 Oct 2026
- **Updated:** 7 Oct 2026
- **Also known as:** GHSA-7649-wm97-w3j3

## What is CVE-2026-106494?

CVE-2026-106494 is a medium-severity path traversal vulnerability in Linuxfoundation Backstage, published on 6 Oct 2026. An attacker needs administrator access to exploit it, with no action from the victim.

### Official description

Backstage is an open framework for building developer portals. Prior to 0.17.8, the @backstage/backend-defaults package is affected by improper input validation in cloud storage url readers. An attacker with write access to a cloud storage bucket used by Backstage could craft object names that could collide with protected files in the output directory. In certain deployment configurations, this could lead to content injection. This issue is fixed in version 0.17.8.

Weakness: CWE-73 (External Control of File Name or Path), CWE-22 (Improper Limitation of a Pathname to a Restricted Directory)

## Which versions are affected by CVE-2026-106494?

2 open source packages ship an affected version, including @backstage/backend-defaults. It affects 2 products.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `@backstage/backend-defaults` | npm | All versions | 0.17.8 |
| `@backstage/backend-defaults` | npm | All versions | 0.17.8 |

Products: Linuxfoundation Backstage, Linuxfoundation Backstage\/Backend Defaults.

## How do I fix CVE-2026-106494?

Upgrade @backstage/backend-defaults to 0.17.8 or later.

## Is CVE-2026-106494 being exploited?

There is no known exploitation of CVE-2026-106494 in the wild and no public exploit code.

## Other vulnerabilities in Linuxfoundation Backstage

- [CVE-2026-106501](https://insights.sbomify.com/CVE-2026-106501/): Backstage: Sensitive information exposure in Scaffolder (critical 9.6)
- [CVE-2026-106558](https://insights.sbomify.com/CVE-2026-106558/): Backstage: Improper validation of TechDocs MkDocs configuration (high 8.8)
- [CVE-2026-88064](https://insights.sbomify.com/CVE-2026-88064/): Backstage: Improper input validation in TechDocs MkDocs configuration (high 8.8)
- [CVE-2026-106459](https://insights.sbomify.com/CVE-2026-106459/): Backstage: Improper input validation in Sentry scaffolder actions (high 8.5)
- [CVE-2026-106486](https://insights.sbomify.com/CVE-2026-106486/): Backstage: Improper filesystem validation in Bitbucket pull-request scaffolder actions (high 8.5)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-106494 and fix it if it is affected.

What it is: CVE-2026-106494 is a medium-severity path traversal vulnerability in Linuxfoundation Backstage, published on 6 Oct 2026. An attacker needs administrator access to exploit it, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2026-106494 in the wild and no public exploit code.

Affected packages and fixed versions:
- @backstage/backend-defaults (npm): affected all versions; fixed in 0.17.8
- @backstage/backend-defaults (npm): affected all versions; fixed in 0.17.8

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-2026-106494/ (Markdown: https://insights.sbomify.com/CVE-2026-106494/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-106494
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-106494
- OSV: https://osv.dev/vulnerability/CVE-2026-106494

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-106494/
Summaries are generated and may contain mistakes; the official description above is the record.