Backstage is an open framework for building developer portals. Prior to 1.14.6 and 1.15.4, the @backstage/plugin-techdocs-node package did not sufficiently validate TechDocs Markdown extension configuration. An authenticated user who can register or modify documentation sources may cause a TechDocs build to access resources outside the intended documentation boundary, potentially exposing backend-host data or internal network resources. This issue is fixed in versions 1.14.6 and 1.15.4 when pymdown-extensions 10.21.3 or later is also used, normally through mkdocs-techdocs-core 1.7.0 or later.

Affected: npm: @backstage/plugin-techdocs-node

### Impact

An authenticated user who can register or modify documentation sources may cause a TechDocs build to access resources outside the intended documentation boundary. Depending on deployment configuration, this may expose sensitive backend-host data or internal network resources.

### Patches

Patched in `@backstage/plugin-techdocs-node` version `1.15.4`.

Adopters must also use `pymdown-extensions` version `10.21.3` or newer, normally through `mkdocs-techdocs-core` version `1.7.0` or newer. `@backstage/plugin-techdocs-node` does not control the Python dependencies used by the generator; with an older PyMdown release, snippets may remain vulnerable to file inclusion even after their configuration is sanitized.

### Workarounds

- Generate TechDocs only from trusted repositories with reviewed MkDocs configuration. - Use isolated build environments with restricted filesystem access and network egress. - Prefer externally generated TechDocs with appropriately sandboxed CI.