CVE-2026-106559 Backstage: Improper input validation in Confluence to Markdown scaffolder module
Attackers can manipulate file write operations in Backstage templates by exploiting improper input validation in the Confluence to Markdown module.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Over the internet
- Victim action needed
- A user has to click or open something
- Fix
- Available
What is CVE-2026-106559?
CVE-2026-106559 is a medium-severity path traversal vulnerability in Linuxfoundation Backstage, published on 7 Oct 2026. Any signed-in user can exploit it over the network, and only if a user opens a file or follows a link.
Official description
Backstage is an open framework for building developer portals. Prior to 0.3.25, the @backstage/plugin-scaffolder-backend-module-confluence-to-markdown package is affected by improper input validation in confluence to markdown scaffolder module. Insufficient input validation in the Confluence to Markdown scaffolder module could allow an attacker to influence file write operations during template execution. Exploitation requires a Backstage user to run a template that processes attacker-influenced Confluence content. This issue is fixed in version 0.3.25.
Which versions are affected by CVE-2026-106559?
2 open source packages ship an affected version, including @backstage/plugin-scaffolder-backend-module-confluence-to-markdown. It affects 2 products.
| Package | Affected | Fixed in |
|---|---|---|
@backstage/plugin-scaffolder-backend-module-confluence-to-markdown npm | All versions | 0.3.25 |
@backstage/plugin-scaffolder-backend-module-confluence-to-markdown npm | All versions | 0.3.25 |
Products include Linuxfoundation Backstage, Linuxfoundation Backstage\/Plugin-Scaffolder-Backend-Module-Confluence-to-Markdown.
How do I fix CVE-2026-106559?
Upgrade @backstage/plugin-scaffolder-backend-module-confluence-to-markdown to 0.3.25 or later.
Upgrade, and resolve every user-supplied path against an allowed base folder before opening it. More about Path traversal.
Is CVE-2026-106559 being exploited?
There is no known exploitation of CVE-2026-106559 in the wild and no public exploit code.
Other vulnerabilities in Linuxfoundation Backstage
- CVE-2026-106501 Backstage: Sensitive information exposure in Scaffolder
- CVE-2026-106558 Backstage: Improper validation of TechDocs MkDocs configuration
- CVE-2026-88064 Backstage: Improper input validation in TechDocs MkDocs configuration
- CVE-2026-106459 Backstage: Improper input validation in Sentry scaffolder actions
- CVE-2026-106486 Backstage: Improper filesystem validation in Bitbucket pull-request scaffolder actions
Sources
Also known as GHSA-75qf-886x-5xf2.