Backstage: Improper URL validation in catalog entity placeholder resolution
Impact
An authenticated Backstage user could craft a catalog entity with placeholder directives that reference resources outside the entity's source repository. Under certain configurations, this could allow access to data not intended to be available to the user.
Patches
Patched in @backstage/plugin-catalog-backend version 3.9.1
Workarounds
If you're not able to update immediately:
- Limit the scope of integration credentials (e.g., GitHub tokens) to only the repositories that Backstage needs to access.
Affected software
Click a technology to see all vulnerabilities affecting it.
| Platform | Package | Vulnerable versions | Fixed in |
|---|---|---|---|
| npm package | @backstage/plugin-catalog-backend | < 3.9.1 | 3.9.1 |
References
- https://github.com/backstage/backstage/security/advisories/GHSA-qgvj-qcf8-xq73
- https://nvd.nist.gov/vuln/detail/CVE-2026-106498
- https://github.com/backstage/backstage/commit/0b0f6fc89b4eb4872c76a498abbe1dc65998bb6e
- https://github.com/backstage/backstage/commit/286bfc1f9cc3608a073b41016be302785be385d1
- https://github.com/backstage/backstage/commit/61a10f19926aeda7f4a32de48d733e6710584634
- https://github.com/backstage/backstage/commit/99729e925fd2bd40ba210022351a0ee6318e6197
- https://github.com/backstage/backstage/commit/e786ac309ed2d775daf2309393c015c43902d6f6
- https://github.com/backstage/backstage
- https://github.com/backstage/backstage/releases/tag/v1.49.6
- https://github.com/backstage/backstage/releases/tag/v1.50.5
- https://github.com/backstage/backstage/releases/tag/v1.51.3
- https://github.com/backstage/backstage/releases/tag/v1.53.2
- https://github.com/backstage/backstage/releases/tag/v1.54.6
- CVSS vector
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:N/A:N- Weakness (CWE)
CWE-863, CWE-918- Platform
- npm
- Package
@backstage/plugin-catalog-backend- Disclosed
- 07.10.2026
- Updated
- 11.10.2026 10:22
Sources and licenses
OSV / GitHub Advisory Database - GHSA-qgvj-qcf8-xq73 - CC BY 4.0
Vulnerability history: @backstage/plugin-catalog-backend
All published vulnerabilities of this package (npm package), newest first. Shows whether this is a one-off slip or a package that needs watching.
- Total entries
- 4
- First → latest
- 02.2023 10.2026
- Without a fix
- 0
- Exploited in attacks
- 0
Severity breakdown
- High 2
- Medium 1
- Low 1
Disclosures per year
- 2023: 1
- 2024: 1
- 2025: 0
- 2026: 2
-
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