CVE-2026-106486 Backstage: Improper filesystem validation in Bitbucket pull-request scaffolder actions
Authenticated users can exploit improper filesystem validation in Bitbucket scaffolder actions to access or modify files outside the intended directory.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-106486?
CVE-2026-106486 is a high-severity path traversal vulnerability in Linuxfoundation Backstage, published on 6 Oct 2026. Any signed-in user can exploit it over the network, with no action from the victim.
Official description
Backstage is an open framework for building developer portals. Prior to 0.3.10 in @backstage/plugin-scaffolder-backend-module-bitbucket-cloud and 0.2.25 in @backstage/plugin-scaffolder-backend-module-bitbucket-server, the Bitbucket pull-request Scaffolder actions did not sufficiently validate filesystem paths. An authenticated user who can execute an eligible template and influence an allowed Bitbucket repository could affect paths outside the expected working area, potentially compromising backend confidentiality, integrity, or availability. This issue is fixed in @backstage/plugin-scaffolder-backend-module-bitbucket-cloud 0.3.10 and @backstage/plugin-scaffolder-backend-module-bitbucket-server 0.2.25.
Which versions are affected by CVE-2026-106486?
4 open source packages ship an affected version, including @backstage/plugin-scaffolder-backend-module-bitbucket-cloud and @backstage/plugin-scaffolder-backend-module-bitbucket-server. It affects 3 products.
| Package | Affected | Fixed in |
|---|---|---|
@backstage/plugin-scaffolder-backend-module-bitbucket-cloud npm | All versions | 0.3.10 |
@backstage/plugin-scaffolder-backend-module-bitbucket-cloud npm | All versions | 0.3.10 |
@backstage/plugin-scaffolder-backend-module-bitbucket-server npm | All versions | 0.2.25 |
@backstage/plugin-scaffolder-backend-module-bitbucket-server npm | All versions | 0.2.25 |
Products include Linuxfoundation Backstage, Linuxfoundation Backstage\/Plugin-Scaffolder-Backend-Module-Bitbucket-Cloud, Linuxfoundation Backstage\/Plugin-Scaffolder-Backend-Module-Bitbucket-Server.
How do I fix CVE-2026-106486?
Upgrade @backstage/plugin-scaffolder-backend-module-bitbucket-cloud to 0.3.10 or later.
Upgrade, and resolve every user-supplied path against an allowed base folder before opening it. More about Path traversal.
Is CVE-2026-106486 being exploited?
There is no known exploitation of CVE-2026-106486 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-2026-106500 Backstage: Improper task state validation in Scaffolder backend
Sources
Also known as GHSA-g8rx-f7m5-7794.