Vulnerability · Published Oct 6, 2026 · Assigned by GitHub_M
CVE-2026-106486Backstage: Improper filesystem validation in Bitbucket pull-request scaffolder actions
High 8.5
In plain English
A high-severity path traversal in backstage from backstage. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.4% (higher than 31% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.
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.
Affected packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| npm | @backstage/plugin-scaffolder-backend-module-bitbucket-cloud | 0.3.10 | GHSA-g8rx-f7m5-7794 |
| npm | @backstage/plugin-scaffolder-backend-module-bitbucket-server | 0.2.25 | GHSA-g8rx-f7m5-7794 |
Affected products (as reported)
| Vendor | Product | Versions |
|---|---|---|
| backstage | backstage | < 1.54.6 |
| @backstage | plugin-scaffolder-backend-module-bitbucket-cloud | < 0.3.10 |
| @backstage | plugin-scaffolder-backend-module-bitbucket-server | < 0.2.25 |
Weakness: CWE-22, CWE-59 · Vector: CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:H/I:H/A:H